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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.04053">arXiv:2502.04053</a> <span> [<a href="https://arxiv.org/pdf/2502.04053">pdf</a>, <a href="https://arxiv.org/format/2502.04053">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> </div> <p class="title is-5 mathjax"> Proof of principle for a light dark matter search with low-energy positron beams at NA64 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Antonov%2C+A">A. Antonov</a>, <a href="/search/hep-ex?searchtype=author&query=Torres%2C+M+A+A">M. A. Ayala Torres</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bautin%2C+V">V. Bautin</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Bond%C3%AC%2C+M">M. Bond矛</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gertsenberger%2C+S+V">S. V. Gertsenberger</a>, <a href="/search/hep-ex?searchtype=author&query=Girod%2C+S">S. Girod</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a> , et al. (32 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.04053v2-abstract-short" style="display: inline;"> Thermal light dark matter (LDM) with particle masses in the 1 MeV - 1 GeV range could successfully explain the observed dark matter abundance as a relic from the primordial Universe. In this picture, a new feeble interaction acts as a "portal" between the Standard Model and LDM particles, allowing for the exploration of this paradigm at accelerator experiments. In the last years, the "missing ener… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04053v2-abstract-full').style.display = 'inline'; document.getElementById('2502.04053v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.04053v2-abstract-full" style="display: none;"> Thermal light dark matter (LDM) with particle masses in the 1 MeV - 1 GeV range could successfully explain the observed dark matter abundance as a relic from the primordial Universe. In this picture, a new feeble interaction acts as a "portal" between the Standard Model and LDM particles, allowing for the exploration of this paradigm at accelerator experiments. In the last years, the "missing energy" experiment NA64e at CERN SPS (Super Proton Synchrotron) has set world-leading constraints in the vector-mediated LDM parameter space, by exploiting a 100 GeV electron beam impinging on an electromagnetic calorimeter, acting as an active target. In this paper, we report a detailed description of the analysis of a preliminary measurement with a 70 GeV positron beam at NA64e, performed during summer 2023 with an accumulated statistic of 1.6 x 10^10 positrons on target. This data set was analyzed with the primary aim of evaluating the performance of the NA64e detector with a lower energy positron beam, towards the realization of the post-LS3 program. The analysis results, other than additionally probing unexplored regions in the LDM parameter space, provide valuable information towards the future NA64e positron campaign. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04053v2-abstract-full').style.display = 'none'; document.getElementById('2502.04053v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.09772">arXiv:2501.09772</a> <span> [<a href="https://arxiv.org/pdf/2501.09772">pdf</a>, <a href="https://arxiv.org/format/2501.09772">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> Search for $K_{S,L}$ oscillations and invisible decays into the dark sector at NA64 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Krasnikov%2C+N+V">N. V. Krasnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.09772v1-abstract-short" style="display: inline;"> The decays $K_{S,L}$ have never been experimentally tested. In the Standard Model their branching ratios for the decay into two neutrinos are predicted to be extremely small, $Br(K_{S,L} \to 谓\bar谓) \lesssim 10^{-16}$. We consider several natural extensions of the SM, such as two-Higgs-doublet (2HDM), 2HDM and light scalar, and dark mirror sector models, that allow to enhance the $Br(K_{S,L})$ up… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09772v1-abstract-full').style.display = 'inline'; document.getElementById('2501.09772v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.09772v1-abstract-full" style="display: none;"> The decays $K_{S,L}$ have never been experimentally tested. In the Standard Model their branching ratios for the decay into two neutrinos are predicted to be extremely small, $Br(K_{S,L} \to 谓\bar谓) \lesssim 10^{-16}$. We consider several natural extensions of the SM, such as two-Higgs-doublet (2HDM), 2HDM and light scalar, and dark mirror sector models, that allow to enhance the $Br(K_{S,L})$ up to a measurable level. We briefly discuss the possible search for $K_{S,L}$ decays and $K_{S,L}$ oscillations into the dark sector at the NA64 experiment at CERN with the sensitivity to $Br(K_{S,L}) \lesssim 10^{-7}-10^{-5}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09772v1-abstract-full').style.display = 'none'; document.getElementById('2501.09772v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 2 figures. Invited review partly based on arXiv:1409.2288;1503.01595;1602.03548</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Natural Science Review 1, 5 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.08127">arXiv:2501.08127</a> <span> [<a href="https://arxiv.org/pdf/2501.08127">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> Experiment BEST-2 with 58Co neutrino source </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Gavrin%2C+V+N">V. N. Gavrin</a>, <a href="/search/hep-ex?searchtype=author&query=Gorbachev%2C+V+V">V. V. Gorbachev</a>, <a href="/search/hep-ex?searchtype=author&query=Ibragimova%2C+T+V">T. V. Ibragimova</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.08127v1-abstract-short" style="display: inline;"> The article describes a new experiment with an artificial neutrino source 58Co on a gallium target GGNT (SAGE). The goal of the experiment is to study the gallium anomaly. The experiment makes it possible to find the parameters of oscillation transitions of electron neutrinos to sterile states in a wide range of parameters. Including the parameter 螖m2, the experimental determination of which usual… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.08127v1-abstract-full').style.display = 'inline'; document.getElementById('2501.08127v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.08127v1-abstract-full" style="display: none;"> The article describes a new experiment with an artificial neutrino source 58Co on a gallium target GGNT (SAGE). The goal of the experiment is to study the gallium anomaly. The experiment makes it possible to find the parameters of oscillation transitions of electron neutrinos to sterile states in a wide range of parameters. Including the parameter 螖m2, the experimental determination of which usually causes significant difficulties. An important feature of the experiment is the possibility of identifying the dependence of the gallium anomaly on the neutrino energy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.08127v1-abstract-full').style.display = 'none'; document.getElementById('2501.08127v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">The article was accepted in the JETP</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.10128">arXiv:2409.10128</a> <span> [<a href="https://arxiv.org/pdf/2409.10128">pdf</a>, <a href="https://arxiv.org/format/2409.10128">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> Shedding light on Dark Sectors with high-energy muons at the NA64 experiment at the CERN SPS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gertsenberger%2C+S+V">S. V. Gertsenberger</a>, <a href="/search/hep-ex?searchtype=author&query=Girod%2C+S">S. Girod</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Joosten%2C+R">R. Joosten</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kasianova%2C+E+A">E. A. Kasianova</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a> , et al. (32 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.10128v1-abstract-short" style="display: inline;"> A search for Dark Sectors is performed using the unique M2 beam line at the CERN Super Proton Synchrotron. New particles ($X$) could be produced in the bremsstrahlung-like reaction of high energy 160 GeV muons impinging on an active target, $渭N\rightarrow渭NX$, followed by their decays, $X\rightarrow\text{invisible}$. The experimental signature would be a scattered single muon from the target, with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.10128v1-abstract-full').style.display = 'inline'; document.getElementById('2409.10128v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.10128v1-abstract-full" style="display: none;"> A search for Dark Sectors is performed using the unique M2 beam line at the CERN Super Proton Synchrotron. New particles ($X$) could be produced in the bremsstrahlung-like reaction of high energy 160 GeV muons impinging on an active target, $渭N\rightarrow渭NX$, followed by their decays, $X\rightarrow\text{invisible}$. The experimental signature would be a scattered single muon from the target, with about less than half of its initial energy and no activity in the sub-detectors located downstream the interaction point. The full sample of the 2022 run is analyzed through the missing energy/momentum channel, with a total statistics of $(1.98\pm0.02)\times10^{10}$ muons on target. We demonstrate that various muon-philic scenarios involving different types of mediators, such as scalar or vector particles, can be probed simultaneously with such a technique. For the vector-case, besides a $L_渭-L_蟿$ $Z'$ vector boson, we also consider an invisibly decaying dark photon ($A'\rightarrow\text{invisible}$). This search is complementary to NA64 running with electrons and positrons, thus, opening the possibility to expand the exploration of the thermal light dark matter parameter space by combining the results obtained with the three beams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.10128v1-abstract-full').style.display = 'none'; document.getElementById('2409.10128v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 22 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2024-236 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.01990">arXiv:2406.01990</a> <span> [<a href="https://arxiv.org/pdf/2406.01990">pdf</a>, <a href="https://arxiv.org/format/2406.01990">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> 50 GeV $蟺^-$ in, nothing out: a sensitive probe of invisible $畏$ and $畏'$ decays with NA64h </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Antonov%2C+A">A. Antonov</a>, <a href="/search/hep-ex?searchtype=author&query=Torres%2C+M+A+A">M. A. Ayala Torres</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gertsenberger%2C+S+V">S. V. Gertsenberger</a>, <a href="/search/hep-ex?searchtype=author&query=Girod%2C+S">S. Girod</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G+D">G. D. Kekelidze</a> , et al. (32 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.01990v1-abstract-short" style="display: inline;"> We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar $畏$ and $畏'$ mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV $蟺^-$ on nuclei of an active target as the source of neutral mesons. The $畏, 畏' \to invisible$ events would exhibit themselves via a striking signature - the com… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.01990v1-abstract-full').style.display = 'inline'; document.getElementById('2406.01990v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.01990v1-abstract-full" style="display: none;"> We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar $畏$ and $畏'$ mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV $蟺^-$ on nuclei of an active target as the source of neutral mesons. The $畏, 畏' \to invisible$ events would exhibit themselves via a striking signature - the complete disappearance of the incoming beam energy in the detector. No evidence for such events has been found with $2.9\times10^{9}$ pions on target accumulated during one day of data taking. This allows us to set a stringent limit on the branching ratio ${\rm Br}(畏' \to invisible) < 2.1 \times 10^{-4}$ improving the current bound by a factor of $\simeq3$. We also set a limit on ${\rm Br}(畏\to invisible) < 1.1 \times 10^{-4}$ comparable with the existing one. These results demonstrate the great potential of our approach and provide clear guidance on how to enhance and extend the sensitivity for dark sector physics from future searches for invisible neutral meson decays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.01990v1-abstract-full').style.display = 'none'; document.getElementById('2406.01990v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2024-153 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.06982">arXiv:2404.06982</a> <span> [<a href="https://arxiv.org/pdf/2404.06982">pdf</a>, <a href="https://arxiv.org/format/2404.06982">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> First constraints on the $L_渭-L_蟿$ explanation of the muon $g-2$ anomaly from NA64-$e$ at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Antonov%2C+A">A. Antonov</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a> , et al. (36 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.06982v6-abstract-short" style="display: inline;"> The inclusion of an additional $U(1)$ gauge $L_渭-L_蟿$ symmetry would release the tension between the measured and the predicted value of the anomalous muon magnetic moment: this paradigm assumes the existence of a new, light $Z^\prime$ vector boson, with dominant coupling to $渭$ and $蟿$ leptons and interacting with electrons via a loop mechanism. The $L_渭-L_蟿$ model can also explain the Dark Matte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.06982v6-abstract-full').style.display = 'inline'; document.getElementById('2404.06982v6-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.06982v6-abstract-full" style="display: none;"> The inclusion of an additional $U(1)$ gauge $L_渭-L_蟿$ symmetry would release the tension between the measured and the predicted value of the anomalous muon magnetic moment: this paradigm assumes the existence of a new, light $Z^\prime$ vector boson, with dominant coupling to $渭$ and $蟿$ leptons and interacting with electrons via a loop mechanism. The $L_渭-L_蟿$ model can also explain the Dark Matter relic abundance, by assuming that the $Z'$ boson acts as a "portal" to a new Dark Sector of particles in Nature, not charged under known interactions. In this work we present the results of the $Z'$ search performed by the NA64-$e$ experiment at CERN SPS, that collected $\sim 9\times10^{11}$ 100 GeV electrons impinging on an active thick target. Despite the suppressed $Z'$ production yield with an electron beam, NA64-$e$ provides the first accelerator-based results excluding the $g-2$ preferred band of the $Z'$ parameter space in the 1 keV $ < m_{Z'} \lesssim 2$ MeV range, in complementarity with the limits recently obtained by the NA64-$渭$ experiment with a muon beam. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.06982v6-abstract-full').style.display = 'none'; document.getElementById('2404.06982v6-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 5 figures. New version with extended exclusion limits down to 1 keV in Z' mass</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2024-103 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.01708">arXiv:2401.01708</a> <span> [<a href="https://arxiv.org/pdf/2401.01708">pdf</a>, <a href="https://arxiv.org/format/2401.01708">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Exploration of the Muon $g-2$ and Light Dark Matter explanations in NA64 with the CERN SPS high energy muon beam </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Silva%2C+R+B+G">R. B. Galleguillos Silva</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gertsenberger%2C+S+V">S. V. Gertsenberger</a>, <a href="/search/hep-ex?searchtype=author&query=Girod%2C+S">S. Girod</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hoesgen%2C+M">M. Hoesgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kasianova%2C+E+A">E. A. Kasianova</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a> , et al. (32 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.01708v1-abstract-short" style="display: inline;"> We report on a search for a new $Z'$ ($L_渭-L_蟿$) vector boson performed at the NA64 experiment employing a high energy muon beam and a missing energy-momentum technique. Muons from the M2 beamline at the CERN Super Proton Synchrotron with a momentum of 160 GeV/c are directed to an active target. A signal event is a single scattered muon with momentum $<$ 80 GeV/c in the final state, accompanied by… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01708v1-abstract-full').style.display = 'inline'; document.getElementById('2401.01708v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.01708v1-abstract-full" style="display: none;"> We report on a search for a new $Z'$ ($L_渭-L_蟿$) vector boson performed at the NA64 experiment employing a high energy muon beam and a missing energy-momentum technique. Muons from the M2 beamline at the CERN Super Proton Synchrotron with a momentum of 160 GeV/c are directed to an active target. A signal event is a single scattered muon with momentum $<$ 80 GeV/c in the final state, accompanied by missing energy, i.e. no detectable activity in the downstream calorimeters. For a total statistic of $(1.98\pm0.02)\times10^{10}$ muons on target, no event is observed in the expected signal region. This allows us to set new limits on part of the remaining $(m_{Z'},\ g_{Z'})$ parameter space which could provide an explanation for the muon $(g-2)_渭$ anomaly. Additionally, our study excludes part of the parameter space suggested by the thermal Dark Matter relic abundance. Our results pave the way to explore Dark Sectors and light Dark Matter with muon beams in a unique and complementary way to other experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01708v1-abstract-full').style.display = 'none'; document.getElementById('2401.01708v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2023-306 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.15612">arXiv:2308.15612</a> <span> [<a href="https://arxiv.org/pdf/2308.15612">pdf</a>, <a href="https://arxiv.org/format/2308.15612">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> Probing Light Dark Matter with positron beams at NA64 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Antonov%2C+A">A. Antonov</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Bondi%2C+M">M. Bondi</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a> , et al. (41 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.15612v1-abstract-short" style="display: inline;"> We present the results of a missing-energy search for Light Dark Matter which has a new interaction with ordinary matter transmitted by a vector boson, called dark photon $A^\prime$. For the first time, this search is performed with a positron beam by using the significantly enhanced production of $A^\prime$ in the resonant annihilation of positrons with atomic electrons of the target nuclei, foll… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.15612v1-abstract-full').style.display = 'inline'; document.getElementById('2308.15612v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.15612v1-abstract-full" style="display: none;"> We present the results of a missing-energy search for Light Dark Matter which has a new interaction with ordinary matter transmitted by a vector boson, called dark photon $A^\prime$. For the first time, this search is performed with a positron beam by using the significantly enhanced production of $A^\prime$ in the resonant annihilation of positrons with atomic electrons of the target nuclei, followed by the invisible decay of $A^\prime$ into dark matter. No events were found in the signal region with $(10.1 \pm 0.1)~\times~10^{9}$ positrons on target with 100 GeV energy. This allowed us to set new exclusion limits that, relative to the collected statistics, prove the power of this experimental technique. This measurement is a crucial first step toward a future exploration program with positron beams, whose estimated sensitivity is here presented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.15612v1-abstract-full').style.display = 'none'; document.getElementById('2308.15612v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Version submitted to PRL</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2023-192 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.02404">arXiv:2307.02404</a> <span> [<a href="https://arxiv.org/pdf/2307.02404">pdf</a>, <a href="https://arxiv.org/format/2307.02404">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Search for Light Dark Matter with NA64 at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Silva%2C+R+B+G">R. B. Galleguillos Silva</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gertsenberger%2C+S+V">S. V. Gertsenberger</a>, <a href="/search/hep-ex?searchtype=author&query=Girod%2C+S">S. Girod</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%22osgen%2C+M">M. H"osgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a> , et al. (38 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.02404v1-abstract-short" style="display: inline;"> Thermal dark matter models with particle $蠂$ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and ordinary matter. We report on a new search for the sub-GeV $蠂$ production through the interaction mediated by a new vector boson, called the dark photon $A'$, in collisi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.02404v1-abstract-full').style.display = 'inline'; document.getElementById('2307.02404v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.02404v1-abstract-full" style="display: none;"> Thermal dark matter models with particle $蠂$ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and ordinary matter. We report on a new search for the sub-GeV $蠂$ production through the interaction mediated by a new vector boson, called the dark photon $A'$, in collisions of 100 GeV electrons with the active target of the NA64 experiment at the CERN SPS. With $9.37\times10^{11}$ electrons on target collected during 2016-2022 runs NA64 probes for the first time the well-motivated region of parameter space of benchmark thermal scalar and fermionic dark matter models. No evidence for dark matter production has been found. This allows us to set the most sensitive limits on the $A'$ couplings to photons for masses $m_{A'} \lesssim 0.35$ GeV, and to exclude scalar and Majorana dark matter with the $蠂-A'$ coupling $伪_D \leq 0.1$ for masses $0.001 \lesssim m_蠂\lesssim 0.1$ GeV and $3m_蠂\leq m_{A'}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.02404v1-abstract-full').style.display = 'none'; document.getElementById('2307.02404v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 7 figures. arXiv admin note: text overlap with arXiv:1906.00176</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2023-130 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.19411">arXiv:2305.19411</a> <span> [<a href="https://arxiv.org/pdf/2305.19411">pdf</a>, <a href="https://arxiv.org/format/2305.19411">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Accelerator Physics">physics.acc-ph</span> </div> </div> <p class="title is-5 mathjax"> Measurement of the intrinsic hadronic contamination in the NA64$-e$ high-purity $e^+/e^-$ beam at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Bondi%2C+M">M. Bondi</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%22osgen%2C+M">M. H"osgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kambar%2C+Y">Y. Kambar</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a> , et al. (43 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.19411v2-abstract-short" style="display: inline;"> In this study, we present the measurement of the intrinsic hadronic contamination at the CERN SPS H4 beamline configured to transport electrons and positrons at 100 GeV/c momentum. The analysis was performed using data collected by the NA64-$e$ experiment in 2022. Our study is based on calorimetric measurements, exploiting the different interaction mechanisms of electrons and hadrons in the NA64-E… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.19411v2-abstract-full').style.display = 'inline'; document.getElementById('2305.19411v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.19411v2-abstract-full" style="display: none;"> In this study, we present the measurement of the intrinsic hadronic contamination at the CERN SPS H4 beamline configured to transport electrons and positrons at 100 GeV/c momentum. The analysis was performed using data collected by the NA64-$e$ experiment in 2022. Our study is based on calorimetric measurements, exploiting the different interaction mechanisms of electrons and hadrons in the NA64-ECAL and NA64-HCAL detectors. We determined the intrinsic hadronic contamination by comparing the results obtained using the nominal electron/positron beamline configuration with those obtained in a dedicated setup, in which only hadrons impinged on the detector. The significant differences in the experimental signatures of electrons and hadrons motivated our approach, resulting in a small and well-controlled systematic uncertainty for the measurement. Our study allowed us to precisely determine the intrinsic hadronic contamination, which represents a crucial parameter for the NA64 experiment in which the hadron contaminants may result in non-trivial backgrounds. Moreover, we performed dedicated Monte Carlo simulations for the hadron production induced by the primary T2 target. We found a good agreement between measurements and simulation results, confirming the validity of the applied methodology and our evaluation of the intrinsic hadronic contamination. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.19411v2-abstract-full').style.display = 'none'; document.getElementById('2305.19411v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2023-108 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.09979">arXiv:2207.09979</a> <span> [<a href="https://arxiv.org/pdf/2207.09979">pdf</a>, <a href="https://arxiv.org/format/2207.09979">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.129.161801">10.1103/PhysRevLett.129.161801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for a New B-L Z' Gauge Boson with the NA64 Experiment at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Banto-Oberhauser%2C+B">B. Banto-Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Bondi%2C+M">M. Bondi</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V">V. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a> , et al. (33 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.09979v2-abstract-short" style="display: inline;"> A search for a new $Z'$ gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out for the first time using the missing-energy technique in the NA64 experiment at the CERN SPS. From the analysis of the data with 3.22e11 electrons on target collected during 2016-2021 runs no signal events were found. This allows to derive new constraints on the $Z'-e$ coupling stre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.09979v2-abstract-full').style.display = 'inline'; document.getElementById('2207.09979v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.09979v2-abstract-full" style="display: none;"> A search for a new $Z'$ gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out for the first time using the missing-energy technique in the NA64 experiment at the CERN SPS. From the analysis of the data with 3.22e11 electrons on target collected during 2016-2021 runs no signal events were found. This allows to derive new constraints on the $Z'-e$ coupling strength, which for the mass range $0.3 < m_{Z'} < 100$ MeV are more stringent compared to those obtained from the neutrino-electron scattering data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.09979v2-abstract-full').style.display = 'none'; document.getElementById('2207.09979v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 figures. Revised shorter version, Fig.3 updated, published in Physical Review Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2022-156 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Rev.Lett. 129, 161801 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.03101">arXiv:2206.03101</a> <span> [<a href="https://arxiv.org/pdf/2206.03101">pdf</a>, <a href="https://arxiv.org/format/2206.03101">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.106.032015">10.1103/PhysRevD.106.032015 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for a light muon-philic $Z^\prime$ with the NA64-$e$ experiment at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Oberhauser%2C+B+B">B. Banto Oberhauser</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Bisio%2C+P">P. Bisio</a>, <a href="/search/hep-ex?searchtype=author&query=Bond%C3%AC%2C+M">M. Bond矛</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Celentano%2C+A">A. Celentano</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a> , et al. (36 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.03101v3-abstract-short" style="display: inline;"> The extension of Standard Model made by inclusion of additional $U(1)$ gauge $L_渭-L_蟿$ symmetry can explain the difference between the measured and the predicted value of the muon magnetic moment and solve the tension in $B$ meson decays. This model predicts the existence of a new, light $Z^\prime$ vector boson, predominantly coupled to second and third generation leptons, whose interaction with e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.03101v3-abstract-full').style.display = 'inline'; document.getElementById('2206.03101v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.03101v3-abstract-full" style="display: none;"> The extension of Standard Model made by inclusion of additional $U(1)$ gauge $L_渭-L_蟿$ symmetry can explain the difference between the measured and the predicted value of the muon magnetic moment and solve the tension in $B$ meson decays. This model predicts the existence of a new, light $Z^\prime$ vector boson, predominantly coupled to second and third generation leptons, whose interaction with electrons is due to a loop mechanism involving muons and taus. In this work, we present a rigorous evaluation of the upper limits in the $Z^\prime$ parameter space, obtained from the analysis of the data collected by the NA64-$e$ experiment at CERN SPS, that performed a search for light dark matter with $2.84\times10^{11}$ electrons impinging with 100 GeV on an active thick target. The resulting limits, despite being included in a region already investigated by neutrino experiments,touch the muon $g-2$ preferred band for values of the $Z^\prime$ mass of order of 1 MeV. The sensitivity projections for the future high-statistics NA64-$e$ runs demonstrate the power of the electrons/positron beam approach in this theoretical scenario. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.03101v3-abstract-full').style.display = 'none'; document.getElementById('2206.03101v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 9 figures. This version was accepted for publication</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.07364">arXiv:2201.07364</a> <span> [<a href="https://arxiv.org/pdf/2201.07364">pdf</a>, <a href="https://arxiv.org/format/2201.07364">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevC.105.065502">10.1103/PhysRevC.105.065502 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Search for Electron Neutrino Transitions to Sterile States in the BEST Experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barinov%2C+V+V">V. V. Barinov</a>, <a href="/search/hep-ex?searchtype=author&query=Cleveland%2C+B+T">B. T. Cleveland</a>, <a href="/search/hep-ex?searchtype=author&query=Danshin%2C+S+N">S. N. Danshin</a>, <a href="/search/hep-ex?searchtype=author&query=Ejiri%2C+H">H. Ejiri</a>, <a href="/search/hep-ex?searchtype=author&query=Elliott%2C+S+R">S. R. Elliott</a>, <a href="/search/hep-ex?searchtype=author&query=Frekers%2C+D">D. Frekers</a>, <a href="/search/hep-ex?searchtype=author&query=Gavrin%2C+V+N">V. N. Gavrin</a>, <a href="/search/hep-ex?searchtype=author&query=Gorbachev%2C+V+V">V. V. Gorbachev</a>, <a href="/search/hep-ex?searchtype=author&query=Gorbunov%2C+D+S">D. S. Gorbunov</a>, <a href="/search/hep-ex?searchtype=author&query=Haxton%2C+W+C">W. C. Haxton</a>, <a href="/search/hep-ex?searchtype=author&query=Ibragimova%2C+T+V">T. V. Ibragimova</a>, <a href="/search/hep-ex?searchtype=author&query=Kim%2C+I">I. Kim</a>, <a href="/search/hep-ex?searchtype=author&query=Kozlova%2C+Y+P">Yu. P. Kozlova</a>, <a href="/search/hep-ex?searchtype=author&query=Kravchuk%2C+L+V">L. V. Kravchuk</a>, <a href="/search/hep-ex?searchtype=author&query=Kuzminov%2C+V+V">V. V. Kuzminov</a>, <a href="/search/hep-ex?searchtype=author&query=Lubsandorzhiev%2C+B+K">B. K. Lubsandorzhiev</a>, <a href="/search/hep-ex?searchtype=author&query=Malyshkin%2C+Y+M">Yu. M. Malyshkin</a>, <a href="/search/hep-ex?searchtype=author&query=Massarczyk%2C+R">R. Massarczyk</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Mirmov%2C+I+N">I. N. Mirmov</a>, <a href="/search/hep-ex?searchtype=author&query=Nico%2C+J+S">J. S. Nico</a>, <a href="/search/hep-ex?searchtype=author&query=Petelin%2C+A+L">A. L. Petelin</a>, <a href="/search/hep-ex?searchtype=author&query=Robertson%2C+R+G+H">R. G. H. Robertson</a>, <a href="/search/hep-ex?searchtype=author&query=Sinclair%2C+D">D. Sinclair</a>, <a href="/search/hep-ex?searchtype=author&query=Shikhin%2C+A+A">A. A. Shikhin</a> , et al. (5 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.07364v3-abstract-short" style="display: inline;"> The Baksan Experiment on Sterile Transitions (BEST) probes the gallium anomaly and its possible connections to oscillations between active and sterile neutrinos. Based on the Gallium-Germanium Neutrino Telescope (GGNT) technology of the SAGE experiment, BEST employs two zones of liquid Ga target to explore neutrino oscillations on the meter scale. Oscillations on this short scale could produce def… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.07364v3-abstract-full').style.display = 'inline'; document.getElementById('2201.07364v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.07364v3-abstract-full" style="display: none;"> The Baksan Experiment on Sterile Transitions (BEST) probes the gallium anomaly and its possible connections to oscillations between active and sterile neutrinos. Based on the Gallium-Germanium Neutrino Telescope (GGNT) technology of the SAGE experiment, BEST employs two zones of liquid Ga target to explore neutrino oscillations on the meter scale. Oscillations on this short scale could produce deficits in the $^{71}$Ge production rates within the two zones, as well as a possible rate difference between the zones. From July 5th to October 13th 2019, the two-zone target was exposed to a primarily monoenergetic, 3.4-MCi $^{51}$Cr neutrino source 10 times for a total of 20 independent $^{71}$Ge extractions from the two Ga targets. The $^{71}$Ge production rates from the neutrino source were measured from July 2019 to March 2020. At the end of these measurements, the counters were filled with $^{71}$Ge doped gas and calibrated during November 2020. In this paper, results from the BEST sterile neutrino oscillation experiment are presented in details. The ratio of the measured $^{71}$Ge production rates to the predicted rates for the inner and the outer target volumes are calculated from the known neutrino capture cross section. Comparable deficits in the measured ratios relative to predicted values are found for both zones, with the $4 蟽$ deviations from unity consistent with the previously reported gallium anomaly. If interpreted in the context of neutrino oscillations, the deficits give best fit oscillation parameters of $螖m^2=3.3^{+\infty}_{-2.3}$ eV$^2$ and sin$^2 2胃=0.42^{+0.15}_{-0.17}$, consistent with $谓_e \rightarrow 谓_s$ oscillations governed by a surprisingly large mixing angle. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.07364v3-abstract-full').style.display = 'none'; document.getElementById('2201.07364v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.11482">arXiv:2109.11482</a> <span> [<a href="https://arxiv.org/pdf/2109.11482">pdf</a>, <a href="https://arxiv.org/format/2109.11482">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.128.232501">10.1103/PhysRevLett.128.232501 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Results from the Baksan Experiment on Sterile Transitions (BEST) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barinov%2C+V+V">V. V. Barinov</a>, <a href="/search/hep-ex?searchtype=author&query=Cleveland%2C+B+T">B. T. Cleveland</a>, <a href="/search/hep-ex?searchtype=author&query=Danshin%2C+S+N">S. N. Danshin</a>, <a href="/search/hep-ex?searchtype=author&query=Ejiri%2C+H">H. Ejiri</a>, <a href="/search/hep-ex?searchtype=author&query=Elliott%2C+S+R">S. R. Elliott</a>, <a href="/search/hep-ex?searchtype=author&query=Frekers%2C+D">D. Frekers</a>, <a href="/search/hep-ex?searchtype=author&query=Gavrin%2C+V+N">V. N. Gavrin</a>, <a href="/search/hep-ex?searchtype=author&query=Gorbachev%2C+V+V">V. V. Gorbachev</a>, <a href="/search/hep-ex?searchtype=author&query=Gorbunov%2C+D+S">D. S. Gorbunov</a>, <a href="/search/hep-ex?searchtype=author&query=Haxton%2C+W+C">W. C. Haxton</a>, <a href="/search/hep-ex?searchtype=author&query=Ibragimova%2C+T+V">T. V. Ibragimova</a>, <a href="/search/hep-ex?searchtype=author&query=Kim%2C+I">I. Kim</a>, <a href="/search/hep-ex?searchtype=author&query=Kozlova%2C+Y+P">Yu. P. Kozlova</a>, <a href="/search/hep-ex?searchtype=author&query=Kravchuk%2C+L+V">L. V. Kravchuk</a>, <a href="/search/hep-ex?searchtype=author&query=Kuzminov%2C+V+V">V. V. Kuzminov</a>, <a href="/search/hep-ex?searchtype=author&query=Lubsandorzhiev%2C+B+K">B. K. Lubsandorzhiev</a>, <a href="/search/hep-ex?searchtype=author&query=Malyshkin%2C+Y+M">Yu. M. Malyshkin</a>, <a href="/search/hep-ex?searchtype=author&query=Massarczyk%2C+R">R. Massarczyk</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Mirmov%2C+I+N">I. N. Mirmov</a>, <a href="/search/hep-ex?searchtype=author&query=Nico%2C+J+S">J. S. Nico</a>, <a href="/search/hep-ex?searchtype=author&query=Petelin%2C+A+L">A. L. Petelin</a>, <a href="/search/hep-ex?searchtype=author&query=Robertson%2C+R+G+H">R. G. H. Robertson</a>, <a href="/search/hep-ex?searchtype=author&query=Sinclair%2C+D">D. Sinclair</a>, <a href="/search/hep-ex?searchtype=author&query=Shikhin%2C+A+A">A. A. Shikhin</a> , et al. (5 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.11482v2-abstract-short" style="display: inline;"> The Baksan Experiment on Sterile Transitions (BEST) was designed to investigate the deficit of electron neutrinos, $谓_{e}$, observed in previous gallium-based radiochemical measurements with high-intensity neutrino sources, commonly referred to as the \textit{gallium anomaly}, which could be interpreted as evidence for oscillations between $谓_e$ and sterile neutrino ($谓_s$) states. A 3.414-MCi \nu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.11482v2-abstract-full').style.display = 'inline'; document.getElementById('2109.11482v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.11482v2-abstract-full" style="display: none;"> The Baksan Experiment on Sterile Transitions (BEST) was designed to investigate the deficit of electron neutrinos, $谓_{e}$, observed in previous gallium-based radiochemical measurements with high-intensity neutrino sources, commonly referred to as the \textit{gallium anomaly}, which could be interpreted as evidence for oscillations between $谓_e$ and sterile neutrino ($谓_s$) states. A 3.414-MCi \nuc{51}{Cr} $谓_e$ source was placed at the center of two nested Ga volumes and measurements were made of the production of \nuc{71}{Ge} through the charged current reaction, \nuc{71}{Ga}($谓_e$,e$^-$)\nuc{71}{Ge}, at two average distances. The measured production rates for the inner and the outer targets respectively are ($54.9^{+2.5}_{-2.4}(\mbox{stat})\pm1.4 (\mbox{syst})$) and ($55.6^{+2.7}_{-2.6}(\mbox{stat})\pm1.4 (\mbox{syst})$) atoms of \nuc{71}{Ge}/d. The ratio ($R$) of the measured rate of \nuc{71}{Ge} production at each distance to the expected rate from the known cross section and experimental efficiencies are $R_{in}=0.79\pm0.05$ and $R_{out}= 0.77\pm0.05$. The ratio of the outer to the inner result is 0.97$\pm$0.07, which is consistent with unity within uncertainty. The rates at each distance were found to be similar, but 20-24\% lower than expected, thus reaffirming the anomaly. These results are consistent with $谓_e \rightarrow 谓_s$ oscillations with a relatively large $螖m^2$ ($>$0.5 eV$^2$) and mixing sin$^2 2胃$ ($\approx$0.4). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.11482v2-abstract-full').style.display = 'none'; document.getElementById('2109.11482v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Paper updated to final version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.02021">arXiv:2107.02021</a> <span> [<a href="https://arxiv.org/pdf/2107.02021">pdf</a>, <a href="https://arxiv.org/format/2107.02021">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1140/epjc/s10052-021-09705-5">10.1140/epjc/s10052-021-09705-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Cazzaniga%2C+C">C. Cazzaniga</a>, <a href="/search/hep-ex?searchtype=author&query=Odagiu%2C+P">P. Odagiu</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Bueno%2C+L+M">L. Molina Bueno</a>, <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Girod%2C+S">S. Girod</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a> , et al. (33 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.02021v2-abstract-short" style="display: inline;"> We report the results of a search for a new vector boson ($A'$) decaying into two dark matter particles $蠂_1 蠂_2$ of different mass. The heavier $蠂_2$ particle subsequently decays to $蠂_1$ and $A' \to e^- e^+$. For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remark… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.02021v2-abstract-full').style.display = 'inline'; document.getElementById('2107.02021v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.02021v2-abstract-full" style="display: none;"> We report the results of a search for a new vector boson ($A'$) decaying into two dark matter particles $蠂_1 蠂_2$ of different mass. The heavier $蠂_2$ particle subsequently decays to $蠂_1$ and $A' \to e^- e^+$. For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remarkably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained re-analyzing the previous NA64 searches for an invisible decay $A'\to 蠂\overline蠂$ and axion-like or pseudo-scalar particles $a \to 纬纬$. With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for $A'$ masses from 2$m_e$ up to 390 MeV and mixing parameter $蔚$ between $3\times10^{-5}$ and $2\times10^{-2}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.02021v2-abstract-full').style.display = 'none'; document.getElementById('2107.02021v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.13342">arXiv:2104.13342</a> <span> [<a href="https://arxiv.org/pdf/2104.13342">pdf</a>, <a href="https://arxiv.org/format/2104.13342">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.104.L111102">10.1103/PhysRevD.104.L111102 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for pseudoscalar bosons decaying into $e^+e^-$ pairs in the NA64 experiment at the CERN SPS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hoesgen%2C+M">M. Hoesgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a> , et al. (30 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2104.13342v3-abstract-short" style="display: inline;"> We report the results of a search for a light pseudoscalar particle $a$ that couples to electrons and decays to $e^+e^-$ performed using the high-energy CERN SPS H4 electron beam. If such pseudoscalar with a mass $\simeq 17$ MeV exists, it could explain the ATOMKI anomaly. We used the NA64 data samples collected in the "visible mode" configuration with total statistics corresponding to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.13342v3-abstract-full').style.display = 'inline'; document.getElementById('2104.13342v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.13342v3-abstract-full" style="display: none;"> We report the results of a search for a light pseudoscalar particle $a$ that couples to electrons and decays to $e^+e^-$ performed using the high-energy CERN SPS H4 electron beam. If such pseudoscalar with a mass $\simeq 17$ MeV exists, it could explain the ATOMKI anomaly. We used the NA64 data samples collected in the "visible mode" configuration with total statistics corresponding to $8.4\times 10^{10}$ electrons on target (EOT) in 2017 and 2018. In order to increase sensitivity to small coupling parameter $蔚$ we used also the data collected in 2016-2018 in the "invisible mode" configuration of NA64 with a total statistics corresponding to $2.84\times 10^{11}$ EOT. A thorough analysis of both these data samples in the sense of background and efficiency estimations was already performed and reported in our previous papers devoted to the search for light vector particles and axion-like particles (ALP). In this work we recalculate the signal yields, which are different due to different cross section and life time of a pseudoscalar particle $a$, and perform a new statistical analysis. As a result, the region of the two dimensional parameter space $m_a - 蔚$ in the mass range from 1 to 17.1 MeV is excluded. At the mass of the ATOMKI anomaly the values of $蔚$ in the range $2.1 \times 10^{-4} < 蔚< 3.2 \times 10^{-4}$ are excluded. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.13342v3-abstract-full').style.display = 'none'; document.getElementById('2104.13342v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 2 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.01885">arXiv:2102.01885</a> <span> [<a href="https://arxiv.org/pdf/2102.01885">pdf</a>, <a href="https://arxiv.org/format/2102.01885">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.126.211802">10.1103/PhysRevLett.126.211802 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraints on New Physics in the Electron g-2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, Vector, and Axial Vector </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreev%2C+Y+M">Yu. M. Andreev</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a> , et al. (27 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.01885v1-abstract-short" style="display: inline;"> We performed a search for a new generic $X$ boson, which could be a scalar ($S$), pseudoscalar ($P$), vector ($V$) or an axial vector ($A$) particle produced in the 100 GeV electron scattering off nuclei, $e^- Z \to e^- Z X$, followed by its invisible decay in the NA64 experiment at CERN. No evidence for such process was found in the full NA64 data set of $2.84\times 10^{11}$ electrons on target.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.01885v1-abstract-full').style.display = 'inline'; document.getElementById('2102.01885v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.01885v1-abstract-full" style="display: none;"> We performed a search for a new generic $X$ boson, which could be a scalar ($S$), pseudoscalar ($P$), vector ($V$) or an axial vector ($A$) particle produced in the 100 GeV electron scattering off nuclei, $e^- Z \to e^- Z X$, followed by its invisible decay in the NA64 experiment at CERN. No evidence for such process was found in the full NA64 data set of $2.84\times 10^{11}$ electrons on target. We place new bounds on the $S, P, V, A$ coupling strengths to electrons, and set constraints on their contributions to the electron anomalous magnetic moment $a_e$, $|螖a_{X}| \lesssim 10^{-15} - 10^{-13}$ for the $X$ mass region $m_X\lesssim 1$ GeV. These results are an order of magnitude more sensitive compared to the current accuracy on $a_e$ from the electron $g-2$ experiments and recent high-precision determination of the fine structure constant. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.01885v1-abstract-full').style.display = 'none'; document.getElementById('2102.01885v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2021-017 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 126, 211802 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.11877">arXiv:2101.11877</a> <span> [<a href="https://arxiv.org/pdf/2101.11877">pdf</a>, <a href="https://arxiv.org/format/2101.11877">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1140/epja/s10050-021-00475-y">10.1140/epja/s10050-021-00475-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> PANDA Phase One </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barucca%2C+G">G. Barucca</a>, <a href="/search/hep-ex?searchtype=author&query=Dav%C3%AC%2C+F">F. Dav矛</a>, <a href="/search/hep-ex?searchtype=author&query=Lancioni%2C+G">G. Lancioni</a>, <a href="/search/hep-ex?searchtype=author&query=Mengucci%2C+P">P. Mengucci</a>, <a href="/search/hep-ex?searchtype=author&query=Montalto%2C+L">L. Montalto</a>, <a href="/search/hep-ex?searchtype=author&query=Natali%2C+P+P">P. P. Natali</a>, <a href="/search/hep-ex?searchtype=author&query=Paone%2C+N">N. Paone</a>, <a href="/search/hep-ex?searchtype=author&query=Rinaldi%2C+D">D. Rinaldi</a>, <a href="/search/hep-ex?searchtype=author&query=Scalise%2C+L">L. Scalise</a>, <a href="/search/hep-ex?searchtype=author&query=Krusche%2C+B">B. Krusche</a>, <a href="/search/hep-ex?searchtype=author&query=Steinacher%2C+M">M. Steinacher</a>, <a href="/search/hep-ex?searchtype=author&query=Liu%2C+Z">Z. Liu</a>, <a href="/search/hep-ex?searchtype=author&query=Liu%2C+C">C. Liu</a>, <a href="/search/hep-ex?searchtype=author&query=Liu%2C+B">B. Liu</a>, <a href="/search/hep-ex?searchtype=author&query=Shen%2C+X">X. Shen</a>, <a href="/search/hep-ex?searchtype=author&query=Sun%2C+S">S. Sun</a>, <a href="/search/hep-ex?searchtype=author&query=Zhao%2C+G">G. Zhao</a>, <a href="/search/hep-ex?searchtype=author&query=Zhao%2C+J">J. Zhao</a>, <a href="/search/hep-ex?searchtype=author&query=Albrecht%2C+M">M. Albrecht</a>, <a href="/search/hep-ex?searchtype=author&query=Alkakhi%2C+W">W. Alkakhi</a>, <a href="/search/hep-ex?searchtype=author&query=B%C3%B6kelmann%2C+S">S. B枚kelmann</a>, <a href="/search/hep-ex?searchtype=author&query=Coen%2C+S">S. Coen</a>, <a href="/search/hep-ex?searchtype=author&query=Feldbauer%2C+F">F. Feldbauer</a>, <a href="/search/hep-ex?searchtype=author&query=Fink%2C+M">M. Fink</a>, <a href="/search/hep-ex?searchtype=author&query=Frech%2C+J">J. Frech</a> , et al. (399 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.11877v4-abstract-short" style="display: inline;"> The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of hadron-, nuclear- and atomic physics experiments. The future antiProton ANnihilations at DArmstadt (PANDA or $\overline{\rm P}$ANDA) experiment at FAIR will offer a broad physics programme, covering different aspects of the strong interaction. Understanding the latter in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.11877v4-abstract-full').style.display = 'inline'; document.getElementById('2101.11877v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.11877v4-abstract-full" style="display: none;"> The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of hadron-, nuclear- and atomic physics experiments. The future antiProton ANnihilations at DArmstadt (PANDA or $\overline{\rm P}$ANDA) experiment at FAIR will offer a broad physics programme, covering different aspects of the strong interaction. Understanding the latter in the non-perturbative regime remains one of the greatest challenges in contemporary physics. The antiproton-nucleon interaction studied with PANDA provides crucial tests in this area. Furthermore, the high-intensity, low-energy domain of PANDA allows for searches for physics beyond the Standard Model, e.g. through high precision symmetry tests. This paper takes into account a staged approach for the detector setup and for the delivered luminosity from the accelerator. The available detector setup at the time of the delivery of the first antiproton beams in the HESR storage ring is referred to as the \textit{Phase One} setup. The physics programme that is achievable during Phase One is outlined in this paper. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.11877v4-abstract-full').style.display = 'none'; document.getElementById('2101.11877v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 pages, 15 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> European Physics Journal A57, 44 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2005.02710">arXiv:2005.02710</a> <span> [<a href="https://arxiv.org/pdf/2005.02710">pdf</a>, <a href="https://arxiv.org/format/2005.02710">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.125.081801">10.1103/PhysRevLett.125.081801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for Axionlike and Scalar Particles with the NA64 Experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a> , et al. (30 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2005.02710v3-abstract-short" style="display: inline;"> We carried out a model-independent search for light scalar (s) and pseudoscalar axionlike (a) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through the Primakoff effect in interactions of hard bremsstrahlung photons generated by 100 GeV electrons in the NA64 active dump with virtual photons provided by t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.02710v3-abstract-full').style.display = 'inline'; document.getElementById('2005.02710v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2005.02710v3-abstract-full" style="display: none;"> We carried out a model-independent search for light scalar (s) and pseudoscalar axionlike (a) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through the Primakoff effect in interactions of hard bremsstrahlung photons generated by 100 GeV electrons in the NA64 active dump with virtual photons provided by the nuclei of the dump. The a(s) would penetrate the downstream HCAL module, serving as shielding, and would be observed either through their $a(s)\to纬纬$ decay in the rest of the HCAL detector or as events with large missing energy if the a(s) decays downstream of the HCAL. This method allows for the probing the a(s) parameter space, including those from generic axion models, inaccessible to previous experiments. No evidence of such processes has been found from the analysis of the data corresponding to $2.84\times10^{11}$ electrons on target allowing to set new limits on the $a(s)纬纬$-coupling strength for a(s) masses below 55 MeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.02710v3-abstract-full').style.display = 'none'; document.getElementById('2005.02710v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This publication is dedicated to the memory of our colleague Danila Tlisov. 7 pages, 5 figures, revised version accepted for publication in Phys. Rev. Lett</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2020-068 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 125, 081801 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.11389">arXiv:1912.11389</a> <span> [<a href="https://arxiv.org/pdf/1912.11389">pdf</a>, <a href="https://arxiv.org/format/1912.11389">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.101.071101">10.1103/PhysRevD.101.071101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Improved limits on a hypothetical X(16.7) boson and a dark photon decaying into $e^+e^-$ pairs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Bernhard%2C+J">J. Bernhard</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hoesgen%2C+M">M. Hoesgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a> , et al. (29 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.11389v2-abstract-short" style="display: inline;"> The improved results on a direct search for a new X(16.7 MeV) boson which could explain the anomalous excess of $e^+e^-$ pairs observed in the excited 8Be nucleus decays ("Berillium anomaly") are reported. Due to its coupling to electrons, the X boson could be produced in the bremsstrahlung reaction e-Z -> e-ZX by a high-energy beam of electrons incident on active target in the NA64 experiment at… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.11389v2-abstract-full').style.display = 'inline'; document.getElementById('1912.11389v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.11389v2-abstract-full" style="display: none;"> The improved results on a direct search for a new X(16.7 MeV) boson which could explain the anomalous excess of $e^+e^-$ pairs observed in the excited 8Be nucleus decays ("Berillium anomaly") are reported. Due to its coupling to electrons, the X boson could be produced in the bremsstrahlung reaction e-Z -> e-ZX by a high-energy beam of electrons incident on active target in the NA64 experiment at the CERN SPS and observed through its subsequent decay into $e^+e^-$ pair. No evidence for such decays was found from the combined analysis of the data samples with total statistics corresponding to 8.4\times 10^{10} electrons on target collected in 2017 and 2018. This allows to set the new limits on the $X$--$e^-$ coupling in the range 1.2 \times 10^{-4} < 蔚_e < 6.8 \times 10^{-4}, excluding part of the parameter space favored by the Berillium anomaly. We also set new bounds on the mixing strength of photons with dark photons (A') from non-observation of the decay $A' \to e^+e^-$ of the bremsstrahlung A' with a mass below 24 MeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.11389v2-abstract-full').style.display = 'none'; document.getElementById('1912.11389v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 5 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:1803.07748</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2019-284 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. D 101, 071101 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.00176">arXiv:1906.00176</a> <span> [<a href="https://arxiv.org/pdf/1906.00176">pdf</a>, <a href="https://arxiv.org/format/1906.00176">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.123.121801">10.1103/PhysRevLett.123.121801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dark matter search in missing energy events with NA64 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Konorov%2C+I+V">I. V. Konorov</a>, <a href="/search/hep-ex?searchtype=author&query=Kovalenko%2C+S+G">S. G. Kovalenko</a> , et al. (26 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.00176v3-abstract-short" style="display: inline;"> A search for sub-GeV dark matter production mediated by a new vector boson $A'$, called dark photon, is performed by the NA64 experiment in missing energy events from 100 GeV electron interactions in an active beam dump at the CERN SPS. From the analysis of the data collected in the years 2016, 2017, and 2018 with $2.84\times10^{11}$ electrons on target no evidence of such a process has been found… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.00176v3-abstract-full').style.display = 'inline'; document.getElementById('1906.00176v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.00176v3-abstract-full" style="display: none;"> A search for sub-GeV dark matter production mediated by a new vector boson $A'$, called dark photon, is performed by the NA64 experiment in missing energy events from 100 GeV electron interactions in an active beam dump at the CERN SPS. From the analysis of the data collected in the years 2016, 2017, and 2018 with $2.84\times10^{11}$ electrons on target no evidence of such a process has been found. The most stringent constraints on the $A'$ mixing strength with photons and the parameter space for the scalar and fermionic dark matter in the mass range $\lesssim 0.2$ GeV are derived, thus demonstrating the power of the active beam dump approach for the dark matter search. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.00176v3-abstract-full').style.display = 'none'; document.getElementById('1906.00176v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 4 figures, version accepted for publication in Phys. Rev. Lett. arXiv admin note: text overlap with arXiv:1710.00971, arXiv:1610.02988</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2019-116 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 123, 121801 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1803.07748">arXiv:1803.07748</a> <span> [<a href="https://arxiv.org/pdf/1803.07748">pdf</a>, <a href="https://arxiv.org/format/1803.07748">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.120.231802">10.1103/PhysRevLett.120.231802 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for a Hypothetical 16.7 MeV Gauge Boson and Dark Photons in the NA64 Experiment at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Enik%2C+T">T. Enik</a>, <a href="/search/hep-ex?searchtype=author&query=Charitonidis%2C+N">N. Charitonidis</a>, <a href="/search/hep-ex?searchtype=author&query=Feshchenko%2C+A">A. Feshchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Jeckel%2C+M">M. Jeckel</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Kekelidze%2C+G">G. Kekelidze</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Konorov%2C+I+V">I. V. Konorov</a>, <a href="/search/hep-ex?searchtype=author&query=Kovalenko%2C+S+G">S. G. Kovalenko</a> , et al. (23 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1803.07748v2-abstract-short" style="display: inline;"> We report the first results on a direct search for a new 16.7 MeV boson (X) which could explain the anomalous excess of e+e- pairs observed in the excited Be-8 nucleus decays. Due to its coupling to electrons, the X could be produced in the bremsstrahlung reaction e- Z -> e- Z X by a 100 GeV e- beam incident on an active target in the NA64 experiment at the CERN SPS and observed through the subseq… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.07748v2-abstract-full').style.display = 'inline'; document.getElementById('1803.07748v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1803.07748v2-abstract-full" style="display: none;"> We report the first results on a direct search for a new 16.7 MeV boson (X) which could explain the anomalous excess of e+e- pairs observed in the excited Be-8 nucleus decays. Due to its coupling to electrons, the X could be produced in the bremsstrahlung reaction e- Z -> e- Z X by a 100 GeV e- beam incident on an active target in the NA64 experiment at the CERN SPS and observed through the subsequent decay into an e+e- pair. With 5.4\times 10^{10} electrons on target, no evidence for such decays was found, allowing to set first limits on the X-e^- coupling in the range 1.3\times 10^{-4} < 蔚_e < 4.2\times 10^{-4} excluding part of the allowed parameter space. We also set new bounds on the mixing strength of photons with dark photons (A') from non-observation of the decay A'->e+e- of the bremsstrahlung A' with a mass <~ 23 MeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.07748v2-abstract-full').style.display = 'none'; document.getElementById('1803.07748v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 figures. Title changed as suggested by Journal; references added; version published in Phys. Rev. Lett</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-EP-2018-043 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 120, 231802 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1710.00971">arXiv:1710.00971</a> <span> [<a href="https://arxiv.org/pdf/1710.00971">pdf</a>, <a href="https://arxiv.org/format/1710.00971">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.97.072002">10.1103/PhysRevD.97.072002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for vector mediator of Dark Matter production in invisible decay mode </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=NA64+Collaboration"> NA64 Collaboration</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V+E">V. E. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A+G">A. G. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dubinin%2C+F">F. Dubinin</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Emmenegger%2C+S">S. Emmenegger</a>, <a href="/search/hep-ex?searchtype=author&query=Fabich%2C+A">A. Fabich</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gerassimov%2C+S+G">S. G. Gerassimov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Konorov%2C+I+V">I. V. Konorov</a>, <a href="/search/hep-ex?searchtype=author&query=Kovalenko%2C+S+G">S. G. Kovalenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kramarenko%2C+V+A">V. A. Kramarenko</a> , et al. (19 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1710.00971v2-abstract-short" style="display: inline;"> A search is performed for a new sub-GeV vector boson ($A'$) mediated production of Dark Matter ($蠂$) in the fixed-target experiment, NA64, at the CERN SPS. The $A'$, called dark photon, could be generated in the reaction $ e^- Z \to e^- Z A'$ of 100 GeV electrons dumped against an active target which is followed by the prompt invisible decay $A' \to 蠂\overline蠂$. The experimental signature of this… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.00971v2-abstract-full').style.display = 'inline'; document.getElementById('1710.00971v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.00971v2-abstract-full" style="display: none;"> A search is performed for a new sub-GeV vector boson ($A'$) mediated production of Dark Matter ($蠂$) in the fixed-target experiment, NA64, at the CERN SPS. The $A'$, called dark photon, could be generated in the reaction $ e^- Z \to e^- Z A'$ of 100 GeV electrons dumped against an active target which is followed by the prompt invisible decay $A' \to 蠂\overline蠂$. The experimental signature of this process would be an event with an isolated electron and large missing energy in the detector. From the analysis of the data sample collected in 2016 corresponding to $4.3\times10^{10}$ electrons on target no evidence of such a process has been found. New stringent constraints on the $A'$ mixing strength with photons, $10^{-5}\lesssim 蔚\lesssim 10^{-2}$, for the $A'$ mass range $m_{A'} \lesssim 1$ GeV are derived. For models considering scalar and fermionic thermal Dark Matter interacting with the visible sector through the vector portal the 90% C.L. limits $10^{-11}\lesssim y \lesssim 10^{-6}$ on the dark-matter parameter $y = 蔚^2 伪_D (\frac{m_蠂}{m_{A'}})^4 $ are obtained for the dark coupling constant $伪_D = 0.5$ and dark-matter masses $0.001 \lesssim m_蠂\lesssim 0.5 $ GeV. The lower limits $伪_D \gtrsim 10^{-3} $ for pseudo-Dirac Dark Matter in the mass region $m_蠂\lesssim 0.05 $ GeV are more stringent than the corresponding bounds from beam dump experiments. The results are obtained by using tree level, exact calculations of the $A'$ production cross-sections, which turn out to be significantly smaller compared to the one obtained in the Weizs盲cker-Williams approximation for the mass region $m_{A'} \gtrsim 0.1$ GeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.00971v2-abstract-full').style.display = 'none'; document.getElementById('1710.00971v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 October, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 17 figures, version accepted for publication in PRD</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. D 97, 072002 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.04087">arXiv:1708.04087</a> <span> [<a href="https://arxiv.org/pdf/1708.04087">pdf</a>, <a href="https://arxiv.org/format/1708.04087">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.nima.2017.10.067">10.1016/j.nima.2017.10.067 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Performance of Multiplexed XY Resistive Micromegas detectors in a high intensity beam </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V">V. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A">A. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dubinin%2C+F">F. Dubinin</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Emmenegger%2C+S">S. Emmenegger</a>, <a href="/search/hep-ex?searchtype=author&query=Fabich%2C+A">A. Fabich</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Konorov%2C+I+V">I. V. Konorov</a>, <a href="/search/hep-ex?searchtype=author&query=Kramarenko%2C+V+A">V. A. Kramarenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kuleshov%2C+S+V">S. V. Kuleshov</a>, <a href="/search/hep-ex?searchtype=author&query=Levchenko%2C+E">E. Levchenko</a>, <a href="/search/hep-ex?searchtype=author&query=Lyubovitskij%2C+V+E">V. E. Lyubovitskij</a>, <a href="/search/hep-ex?searchtype=author&query=Lysan%2C+V">V. Lysan</a>, <a href="/search/hep-ex?searchtype=author&query=Mamon%2C+S">S. Mamon</a> , et al. (16 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1708.04087v1-abstract-short" style="display: inline;"> We present the performance of multiplexed XY resistive Micromegas detectors tested in the CERN SPS 100 GeV/c electron beam at intensities up to 3.3 $\times$ 10$^5$ e$^- $/(s$\cdot$cm$^2$). So far, all studies with multiplexed Micromegas have only been reported for tests with radioactive sources and cosmic rays. The use of multiplexed modules in high intensity environments was not explored due to t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.04087v1-abstract-full').style.display = 'inline'; document.getElementById('1708.04087v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.04087v1-abstract-full" style="display: none;"> We present the performance of multiplexed XY resistive Micromegas detectors tested in the CERN SPS 100 GeV/c electron beam at intensities up to 3.3 $\times$ 10$^5$ e$^- $/(s$\cdot$cm$^2$). So far, all studies with multiplexed Micromegas have only been reported for tests with radioactive sources and cosmic rays. The use of multiplexed modules in high intensity environments was not explored due to the effect of ambiguities in the reconstruction of the hit point caused by the multiplexing feature. At the beam intensities analysed in this work and with a multiplexing factor of 5, more than 50% level of ambiguity is introduced. Our results prove that by using the additional information of cluster size and integrated charge from the signal clusters induced on the XY strips, the ambiguities can be reduced to a level below 2%. The tested detectors are used in the CERN NA64 experiment for tracking the incoming particles bending in a magnetic field in order to reconstruct their momentum. The average hit detection efficiency of each module was found to be $\sim$ 96% at the highest beam intensities. By using four modules a tracking resolution of 1.1% was obtained with $\sim$ 85% combined tracking efficiency. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.04087v1-abstract-full').style.display = 'none'; document.getElementById('1708.04087v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.05993">arXiv:1703.05993</a> <span> [<a href="https://arxiv.org/pdf/1703.05993">pdf</a>, <a href="https://arxiv.org/format/1703.05993">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.nima.2017.05.028">10.1016/j.nima.2017.05.028 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High purity 100 GeV electron identification with synchrotron radiation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V">V. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Chumakov%2C+A">A. Chumakov</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dubinin%2C+F">F. Dubinin</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Emmenegger%2C+S">S. Emmenegger</a>, <a href="/search/hep-ex?searchtype=author&query=Fabich%2C+A">A. Fabich</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=H%C3%B6sgen%2C+M">M. H枚sgen</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Konorov%2C+I+V">I. V. Konorov</a>, <a href="/search/hep-ex?searchtype=author&query=Kramarenko%2C+V+A">V. A. Kramarenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kuleshov%2C+S+V">S. V. Kuleshov</a>, <a href="/search/hep-ex?searchtype=author&query=Lyubovitskij%2C+V+E">V. E. Lyubovitskij</a>, <a href="/search/hep-ex?searchtype=author&query=Lysan%2C+V">V. Lysan</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Mikhailov%2C+Y+V">Yu. V. Mikhailov</a> , et al. (14 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1703.05993v1-abstract-short" style="display: inline;"> In high energy experiments such as active beam dump searches for rare decays and missing energy events, the beam purity is a crucial parameter. In this paper we present a technique to reject heavy charged particle contamination in the 100 GeV electron beam of the H4 beam line at CERN SPS. The method is based on the detection with BGO scintillators of the synchrotron radiation emitted by the electr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.05993v1-abstract-full').style.display = 'inline'; document.getElementById('1703.05993v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.05993v1-abstract-full" style="display: none;"> In high energy experiments such as active beam dump searches for rare decays and missing energy events, the beam purity is a crucial parameter. In this paper we present a technique to reject heavy charged particle contamination in the 100 GeV electron beam of the H4 beam line at CERN SPS. The method is based on the detection with BGO scintillators of the synchrotron radiation emitted by the electrons passing through a bending dipole magnet. A 100 GeV $蟺^-$ beam is used to test the method in the NA64 experiment resulting in a suppression factor of $10^{-5}$ while the efficiency for electron detection is $\sim$95%. The spectra and the rejection factors are in very good agreement with the Monte Carlo simulation. The reported suppression factors are significantly better than previously achieved. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.05993v1-abstract-full').style.display = 'none'; document.getElementById('1703.05993v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1610.02988">arXiv:1610.02988</a> <span> [<a href="https://arxiv.org/pdf/1610.02988">pdf</a>, <a href="https://arxiv.org/format/1610.02988">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.118.011802">10.1103/PhysRevLett.118.011802 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Search for invisible decays of sub-GeV dark photons in missing-energy events at the CERN SPS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=NA64+Collaboration"> NA64 Collaboration</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</a>, <a href="/search/hep-ex?searchtype=author&query=Burtsev%2C+V">V. Burtsev</a>, <a href="/search/hep-ex?searchtype=author&query=Cooke%2C+D">D. Cooke</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Depero%2C+E">E. Depero</a>, <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Dubinin%2C+F">F. Dubinin</a>, <a href="/search/hep-ex?searchtype=author&query=Dusaev%2C+R+R">R. R. Dusaev</a>, <a href="/search/hep-ex?searchtype=author&query=Emmenegger%2C+S">S. Emmenegger</a>, <a href="/search/hep-ex?searchtype=author&query=Fabich%2C+A">A. Fabich</a>, <a href="/search/hep-ex?searchtype=author&query=Frolov%2C+V+N">V. N. Frolov</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Hosgen%2C+M">M. Hosgen</a>, <a href="/search/hep-ex?searchtype=author&query=Kachanov%2C+V+A">V. A. Kachanov</a>, <a href="/search/hep-ex?searchtype=author&query=Karneyeu%2C+A+E">A. E. Karneyeu</a>, <a href="/search/hep-ex?searchtype=author&query=Ketzer%2C+B">B. Ketzer</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kovalenko%2C+S+G">S. G. Kovalenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kramarenko%2C+V+A">V. A. Kramarenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kravchuk%2C+L+V">L. V. Kravchuk</a>, <a href="/search/hep-ex?searchtype=author&query=Krasnikov%2C+N+V">N. V. Krasnikov</a> , et al. (22 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1610.02988v2-abstract-short" style="display: inline;"> We report on a direct search for sub-GeV dark photons (A') which might be produced in the reaction e^- Z \to e^- Z A' via kinetic mixing with photons by 100 GeV electrons incident on an active target in the NA64 experiment at the CERN SPS. The A's would decay invisibly into dark matter particles resulting in events with large missing energy. No evidence for such decays was found with 2.75\cdot 10^… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.02988v2-abstract-full').style.display = 'inline'; document.getElementById('1610.02988v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.02988v2-abstract-full" style="display: none;"> We report on a direct search for sub-GeV dark photons (A') which might be produced in the reaction e^- Z \to e^- Z A' via kinetic mixing with photons by 100 GeV electrons incident on an active target in the NA64 experiment at the CERN SPS. The A's would decay invisibly into dark matter particles resulting in events with large missing energy. No evidence for such decays was found with 2.75\cdot 10^{9} electrons on target. We set new limits on the 纬-A' mixing strength and exclude the invisible A' with a mass < 100 MeV as an explanation of the muon g_渭-2 anomaly. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.02988v2-abstract-full').style.display = 'none'; document.getElementById('1610.02988v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 figures; Typos corrected, references added</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 118, 011802 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.08632">arXiv:1608.08632</a> <span> [<a href="https://arxiv.org/pdf/1608.08632">pdf</a>, <a href="https://arxiv.org/format/1608.08632">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> </div> </div> <p class="title is-5 mathjax"> Dark Sectors 2016 Workshop: Community Report </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Alexander%2C+J">Jim Alexander</a>, <a href="/search/hep-ex?searchtype=author&query=Battaglieri%2C+M">Marco Battaglieri</a>, <a href="/search/hep-ex?searchtype=author&query=Echenard%2C+B">Bertrand Echenard</a>, <a href="/search/hep-ex?searchtype=author&query=Essig%2C+R">Rouven Essig</a>, <a href="/search/hep-ex?searchtype=author&query=Graham%2C+M">Matthew Graham</a>, <a href="/search/hep-ex?searchtype=author&query=Izaguirre%2C+E">Eder Izaguirre</a>, <a href="/search/hep-ex?searchtype=author&query=Jaros%2C+J">John Jaros</a>, <a href="/search/hep-ex?searchtype=author&query=Krnjaic%2C+G">Gordan Krnjaic</a>, <a href="/search/hep-ex?searchtype=author&query=Mardon%2C+J">Jeremy Mardon</a>, <a href="/search/hep-ex?searchtype=author&query=Morrissey%2C+D">David Morrissey</a>, <a href="/search/hep-ex?searchtype=author&query=Nelson%2C+T">Tim Nelson</a>, <a href="/search/hep-ex?searchtype=author&query=Perelstein%2C+M">Maxim Perelstein</a>, <a href="/search/hep-ex?searchtype=author&query=Pyle%2C+M">Matt Pyle</a>, <a href="/search/hep-ex?searchtype=author&query=Ritz%2C+A">Adam Ritz</a>, <a href="/search/hep-ex?searchtype=author&query=Schuster%2C+P">Philip Schuster</a>, <a href="/search/hep-ex?searchtype=author&query=Shuve%2C+B">Brian Shuve</a>, <a href="/search/hep-ex?searchtype=author&query=Toro%2C+N">Natalia Toro</a>, <a href="/search/hep-ex?searchtype=author&query=Van+De+Water%2C+R+G">Richard G Van De Water</a>, <a href="/search/hep-ex?searchtype=author&query=Akerib%2C+D">Daniel Akerib</a>, <a href="/search/hep-ex?searchtype=author&query=An%2C+H">Haipeng An</a>, <a href="/search/hep-ex?searchtype=author&query=Aniol%2C+K">Konrad Aniol</a>, <a href="/search/hep-ex?searchtype=author&query=Arnquist%2C+I+J">Isaac J. Arnquist</a>, <a href="/search/hep-ex?searchtype=author&query=Asner%2C+D+M">David M. Asner</a>, <a href="/search/hep-ex?searchtype=author&query=Back%2C+H+O">Henning O. Back</a>, <a href="/search/hep-ex?searchtype=author&query=Baker%2C+K">Keith Baker</a> , et al. (179 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.08632v1-abstract-short" style="display: inline;"> This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.08632v1-abstract-full" style="display: none;"> This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.08632v1-abstract-full').style.display = 'none'; document.getElementById('1608.08632v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">66 pages, 15 figures, 3 tables. Workshop website and agenda: http://www-conf.slac.stanford.edu/darksectors2016/ https://indico.cern.ch/event/507783/ Editors: J. Alexander, M. Battaglieri, B. Echenard, R. Essig, M. Graham, E. Izaguirre, J. Jaros, G. Krnjaic, J. Mardon, D. Morrissey, T. Nelson, M. Perelstein, M. Pyle, A. Ritz, P. Schuster, B. Shuve, N. Toro, R. Van De Water</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.08523">arXiv:1608.08523</a> <span> [<a href="https://arxiv.org/pdf/1608.08523">pdf</a>, <a href="https://arxiv.org/ps/1608.08523">ps</a>, <a href="https://arxiv.org/format/1608.08523">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> </div> </div> <p class="title is-5 mathjax"> Search for $螛^+(1540)$ emission in hadron--nucleus collisions at 400--700 GeV </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Asratyan%2C+A+E">A. E. Asratyan</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.08523v1-abstract-short" style="display: inline;"> The data on hadron--nucleus collisions at 400--700 GeV, collected by the SELEX experiment at Fermilab, are analyzed for formation of the exotic pentaquark baryon $螛^+(1540)$. A narrow enhancement near 1539 MeV is observed in the mass spectrum of the $pK^0_S$ system emitted at small $x_F$ from hadron collisions with copper nuclei. The statistical significance of the peak is near 9 standard deviatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.08523v1-abstract-full').style.display = 'inline'; document.getElementById('1608.08523v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.08523v1-abstract-full" style="display: none;"> The data on hadron--nucleus collisions at 400--700 GeV, collected by the SELEX experiment at Fermilab, are analyzed for formation of the exotic pentaquark baryon $螛^+(1540)$. A narrow enhancement near 1539 MeV is observed in the mass spectrum of the $pK^0_S$ system emitted at small $x_F$ from hadron collisions with copper nuclei. The statistical significance of the peak is near 9 standard deviations. Fitted width of the observed $pK^0_S$ resonance is consistent with being entirely due to experimental resolution, and its intrinsic width is restricted to $螕< 3$ MeV at 90\% CL. The data favor positive rather than negative strangeness for the $pK^0_S$ resonance observed in $h$Cu collisions. At the same time, the $pK^0_S$ mass spectrum for collisions in carbon is featureless. The yield of $螛^+$ baryons per $h$C collision is restricted to be $< 24$\% of the yield per $h$Cu collision. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.08523v1-abstract-full').style.display = 'none'; document.getElementById('1608.08523v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1507.06001">arXiv:1507.06001</a> <span> [<a href="https://arxiv.org/pdf/1507.06001">pdf</a>, <a href="https://arxiv.org/ps/1507.06001">ps</a>, <a href="https://arxiv.org/format/1507.06001">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> </div> </div> <p class="title is-5 mathjax"> Angular distribution in s-channel formation of the pentaquark $螛^+$ baryon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=DIANA+Collaboration"> DIANA Collaboration</a>, <a href="/search/hep-ex?searchtype=author&query=Barmin%2C+V+V">V. V. Barmin</a>, <a href="/search/hep-ex?searchtype=author&query=Asratyan%2C+A+E">A. E. Asratyan</a>, <a href="/search/hep-ex?searchtype=author&query=Curceanu%2C+C">C. Curceanu</a>, <a href="/search/hep-ex?searchtype=author&query=Davidenko%2C+G+V">G. V. Davidenko</a>, <a href="/search/hep-ex?searchtype=author&query=Guaraldo%2C+C">C. Guaraldo</a>, <a href="/search/hep-ex?searchtype=author&query=Kubantsev%2C+M+A">M. A. Kubantsev</a>, <a href="/search/hep-ex?searchtype=author&query=Larin%2C+I+F">I. F. Larin</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Shebanov%2C+V+A">V. A. Shebanov</a>, <a href="/search/hep-ex?searchtype=author&query=Shishov%2C+N+N">N. N. Shishov</a>, <a href="/search/hep-ex?searchtype=author&query=Sokolov%2C+L+I">L. I. Sokolov</a>, <a href="/search/hep-ex?searchtype=author&query=Tarasov%2C+V+V">V. V. Tarasov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1507.06001v5-abstract-short" style="display: inline;"> Using the DIANA data on the charge-exchange reaction $K^+n \rightarrow pK^0$ on a bound neutron, in which the s-channel formation of the pentaquark baryon $螛^+(1538)$ has been observed, we analyze the dependence of the background-subtracted $螛^+ \rightarrow pK^0$ signal on the $K^0$ emission angle in the $pK^0$ rest frame. In order to describe the observed $\cos螛_K^\mathrm{cms}$ distribution, invo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.06001v5-abstract-full').style.display = 'inline'; document.getElementById('1507.06001v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1507.06001v5-abstract-full" style="display: none;"> Using the DIANA data on the charge-exchange reaction $K^+n \rightarrow pK^0$ on a bound neutron, in which the s-channel formation of the pentaquark baryon $螛^+(1538)$ has been observed, we analyze the dependence of the background-subtracted $螛^+ \rightarrow pK^0$ signal on the $K^0$ emission angle in the $pK^0$ rest frame. In order to describe the observed $\cos螛_K^\mathrm{cms}$ distribution, invoking the interference between the nonresonant s-wave and the $螛^+$-mediated higher-wave contributions to the amplitude of the charge-exchange reaction is required at a 2.8$蟽$ level. The spin--parity assignment of 1/2$^-$ for the $螛^+$ baryon is ruled out at a statistical level of 2.9 standard deviations. A physically-meaningful selection in $\cos螛_K^\mathrm{cms}$ based on the observed angular dependence of the $螛^+ \rightarrow pK^0$ signal allows to boost the statistical significance of the signal up to 7.1 standard deviations. This is far in excess of previously reported signals and renders the $螛^+$ existence more credible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.06001v5-abstract-full').style.display = 'none'; document.getElementById('1507.06001v5-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 July, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1503.05687">arXiv:1503.05687</a> <span> [<a href="https://arxiv.org/pdf/1503.05687">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1109/TNS.2015.2499794">10.1109/TNS.2015.2499794 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On detection of narrow angle e+e- pairs from dark photon decays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Dermenev%2C+A+V">A. V. Dermenev</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kuleshov%2C+S+B">S. B. Kuleshov</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Myalkovskiy%2C+V+V">V. V. Myalkovskiy</a>, <a href="/search/hep-ex?searchtype=author&query=Peshekhonov%2C+V+D">V. D. Peshekhonov</a>, <a href="/search/hep-ex?searchtype=author&query=Poliakov%2C+V+A">V. A. Poliakov</a>, <a href="/search/hep-ex?searchtype=author&query=Savenkov%2C+A+A">A. A. Savenkov</a>, <a href="/search/hep-ex?searchtype=author&query=Tikhomirov%2C+V+O">V. O. Tikhomirov</a>, <a href="/search/hep-ex?searchtype=author&query=Zhukov%2C+I+A">I. A. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1503.05687v1-abstract-short" style="display: inline;"> A class of models of dark sectors consider new very weak interaction between the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark photons) mixing with our photons. If such A's exist, they could be searched for in a light-shining-through-a-wall experiment with a high energy electron beam from the CERN SPS. The proposed search scheme suggests detection of the e+e- pairs produced i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.05687v1-abstract-full').style.display = 'inline'; document.getElementById('1503.05687v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1503.05687v1-abstract-full" style="display: none;"> A class of models of dark sectors consider new very weak interaction between the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark photons) mixing with our photons. If such A's exist, they could be searched for in a light-shining-through-a-wall experiment with a high energy electron beam from the CERN SPS. The proposed search scheme suggests detection of the e+e- pairs produced in the A' -> e+e- decay with a very small opening angle. Coordinate chambers based on the thin-wall drift tubes with a minimal material budget and a two-hit resolution for e+ and e- tracks separated by more than 0.5 mm are considered as an option for detecting such pairs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.05687v1-abstract-full').style.display = 'none'; document.getElementById('1503.05687v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 March, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2015. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1412.1400">arXiv:1412.1400</a> <span> [<a href="https://arxiv.org/pdf/1412.1400">pdf</a>, <a href="https://arxiv.org/ps/1412.1400">ps</a>, <a href="https://arxiv.org/format/1412.1400">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.91.095015">10.1103/PhysRevD.91.095015 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Muon g-2 and searches for a new leptophobic sub-GeV dark boson in a missing-energy experiment at CERN </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Krasnikov%2C+N+V">N. V. Krasnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1412.1400v2-abstract-short" style="display: inline;"> The 3.6 蟽discrepancy between the predicted and measured values of the anomalous magnetic moment of positive muons can be explained by the existence of a new dark boson Z_渭with a mass in the sub-GeV range, which is coupled predominantly to the second and third lepton generations through the L_渭- L_蟿current . After a discussion of the present phenomenological bounds on the Z_渭coupling, we show that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.1400v2-abstract-full').style.display = 'inline'; document.getElementById('1412.1400v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1412.1400v2-abstract-full" style="display: none;"> The 3.6 蟽discrepancy between the predicted and measured values of the anomalous magnetic moment of positive muons can be explained by the existence of a new dark boson Z_渭with a mass in the sub-GeV range, which is coupled predominantly to the second and third lepton generations through the L_渭- L_蟿current . After a discussion of the present phenomenological bounds on the Z_渭coupling, we show that if the Z_渭exists, it could be observed in the reaction 渭+Z \to 渭+Z+Z_渭of a muon scattering off nuclei by looking for an excess of events with large missing muon beam energy in a detector due to the prompt bremsstrahlung Z_渭decay Z_渭\to 谓谓into a couple of neutrinos. We describe the experimental technique and the preliminary study of the feasibility for the proposed search. We show that this specific signal allows for a the search for the Z_渭with a sensitivity in the coupling constant 伪_渭> 10^{-11}, which is 3 orders of magnitude higher than the value required to explain the discrepancy. We point out that the availability of high-energy and -intensity muon beams at CERN SPS provides a unique opportunity to either discover or rule out the Z_渭in the proposed search in the near future. The experiment is based on the missing-energy approach developed for the searches for invisible decays of dark photons and (pseudo)scalar mesons at CERN and is complementary to these experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.1400v2-abstract-full').style.display = 'none'; document.getElementById('1412.1400v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 May, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 9 figures. Version to appear in PRD, refs. and discussions added, title modified in journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. D91 (2015) 095015 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1312.3309">arXiv:1312.3309</a> <span> [<a href="https://arxiv.org/pdf/1312.3309">pdf</a>, <a href="https://arxiv.org/ps/1312.3309">ps</a>, <a href="https://arxiv.org/format/1312.3309">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> </div> <p class="title is-5 mathjax"> Proposal for an Experiment to Search for Light Dark Matter at the SPS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Andreas%2C+S">S. Andreas</a>, <a href="/search/hep-ex?searchtype=author&query=Donskov%2C+S+V">S. V. Donskov</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Gardikiotis%2C+A">A. Gardikiotis</a>, <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Golubev%2C+N+A">N. A. Golubev</a>, <a href="/search/hep-ex?searchtype=author&query=Guber%2C+F+F">F. F. Guber</a>, <a href="/search/hep-ex?searchtype=author&query=Ivashkin%2C+A+P">A. P. Ivashkin</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Krasnikov%2C+N+V">N. V. Krasnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Mikhailov%2C+Y+V">Yu. V. Mikhailov</a>, <a href="/search/hep-ex?searchtype=author&query=Musienko%2C+Y+V">Yu. V. Musienko</a>, <a href="/search/hep-ex?searchtype=author&query=Polyakov%2C+V+A">V. A. Polyakov</a>, <a href="/search/hep-ex?searchtype=author&query=Ringwald%2C+A">A. Ringwald</a>, <a href="/search/hep-ex?searchtype=author&query=Rubbia%2C+A">A. Rubbia</a>, <a href="/search/hep-ex?searchtype=author&query=Samoylenko%2C+V+D">V. D. Samoylenko</a>, <a href="/search/hep-ex?searchtype=author&query=Semertzidis%2C+Y+K">Y. K. Semertzidis</a>, <a href="/search/hep-ex?searchtype=author&query=Zioutas%2C+K">K. Zioutas</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1312.3309v1-abstract-short" style="display: inline;"> Several models of dark matter suggest the existence of dark sectors consisting of SU(3)_C x SU(2)_L x U(1)_Y singlet fields. These sectors of particles do not interact with the ordinary matter directly but could couple to it via gravity. In addition to gravity, there might be another very weak interaction between the ordinary and dark matter mediated by U'(1) gauge bosons A' (dark photons) mixing… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.3309v1-abstract-full').style.display = 'inline'; document.getElementById('1312.3309v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1312.3309v1-abstract-full" style="display: none;"> Several models of dark matter suggest the existence of dark sectors consisting of SU(3)_C x SU(2)_L x U(1)_Y singlet fields. These sectors of particles do not interact with the ordinary matter directly but could couple to it via gravity. In addition to gravity, there might be another very weak interaction between the ordinary and dark matter mediated by U'(1) gauge bosons A' (dark photons) mixing with our photons. In a class of models the corresponding dark gauge bosons could be light and have the $纬$-A' coupling strength laying in the experimentally accessible and theoretically interesting region. If such A' mediators exist, their di-electron decays A' -> e+e- could be searched for in a light-shining-through-a-wall experiment looking for an excess of events with the two-shower signature generated by a single high energy electron in the detector. A proposal to perform such an experiment aiming to probe the still unexplored area of the mixing strength 10^-5 < $蔚$ < 10^-3 and masses M_A' < 100 MeV by using 10-300 GeV electron beams from the CERN SPS is presented. The experiment can provide complementary coverage of the parameter space, which is intended to be probed by other searches. It has also a capability for a sensitive search for A's decaying invisibly to dark-sector particles, such as dark matter, which could cover a significant part of the still allowed parameter space. The full running time of the proposed measurements is requested to be up to several months, and it could be taken at different SPS secondary beams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.3309v1-abstract-full').style.display = 'none'; document.getElementById('1312.3309v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 December, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">42 pages, 19 figures. This work is a continuation of work started in arXiv:1308.6521</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1307.1653">arXiv:1307.1653</a> <span> [<a href="https://arxiv.org/pdf/1307.1653">pdf</a>, <a href="https://arxiv.org/ps/1307.1653">ps</a>, <a href="https://arxiv.org/format/1307.1653">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> Observation of a narrow baryon resonance with positive strangeness formed in $K^+$Xe collisions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=DIANA+Collaboration"> DIANA Collaboration</a>, <a href="/search/hep-ex?searchtype=author&query=Barmin%2C+V+V">V. V. Barmin</a>, <a href="/search/hep-ex?searchtype=author&query=Asratyan%2C+A+E">A. E. Asratyan</a>, <a href="/search/hep-ex?searchtype=author&query=Borisov%2C+V+S">V. S. Borisov</a>, <a href="/search/hep-ex?searchtype=author&query=Curceanu%2C+C">C. Curceanu</a>, <a href="/search/hep-ex?searchtype=author&query=Davidenko%2C+G+V">G. V. Davidenko</a>, <a href="/search/hep-ex?searchtype=author&query=Dolgolenko%2C+A+G">A. G. Dolgolenko</a>, <a href="/search/hep-ex?searchtype=author&query=Guaraldo%2C+C">C. Guaraldo</a>, <a href="/search/hep-ex?searchtype=author&query=Kubantsev%2C+M+A">M. A. Kubantsev</a>, <a href="/search/hep-ex?searchtype=author&query=Larin%2C+I+F">I. F. Larin</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Shebanov%2C+V+A">V. A. Shebanov</a>, <a href="/search/hep-ex?searchtype=author&query=Shishov%2C+N+N">N. N. Shishov</a>, <a href="/search/hep-ex?searchtype=author&query=Sokolov%2C+L+I">L. I. Sokolov</a>, <a href="/search/hep-ex?searchtype=author&query=Tarasov%2C+V+V">V. V. Tarasov</a>, <a href="/search/hep-ex?searchtype=author&query=Tumanov%2C+G+K">G. K. Tumanov</a>, <a href="/search/hep-ex?searchtype=author&query=Verebryusov%2C+V+S">V. S. Verebryusov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1307.1653v3-abstract-short" style="display: inline;"> The charge-exchange reaction K^+ Xe --> K^0 p Xe' is investigated using the data of the DIANA experiment. The distribution of the pK^0 effective mass shows a prominent enhancement near 1538 MeV formed by \sim 80 events above the background, whose width is consistent with being entirely due to the experimental resolution. Under the selections based on a simulation of K^+Xe collisions, the statistic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1307.1653v3-abstract-full').style.display = 'inline'; document.getElementById('1307.1653v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1307.1653v3-abstract-full" style="display: none;"> The charge-exchange reaction K^+ Xe --> K^0 p Xe' is investigated using the data of the DIANA experiment. The distribution of the pK^0 effective mass shows a prominent enhancement near 1538 MeV formed by \sim 80 events above the background, whose width is consistent with being entirely due to the experimental resolution. Under the selections based on a simulation of K^+Xe collisions, the statistical significance of the signal reaches 5.5蟽. We interpret this observation as strong evidence for formation of a pentaquark baryon with positive strangeness, 螛^+(uudd\bar{s}), in the charge-exchange reaction K^+ n --> K^0 p on a bound neutron. The mass of the 螛^+ baryon is measured as m(螛^+) = 1538+-2 MeV. Using the ratio between the numbers of resonant and non-resonant charge-exchange events in the peak region, the intrinsic width of this baryon resonance is determined as 螕(螛^+) = 0.34+-0.10 MeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1307.1653v3-abstract-full').style.display = 'none'; document.getElementById('1307.1653v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 April, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 July, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. C89, 045204 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1306.5602">arXiv:1306.5602</a> <span> [<a href="https://arxiv.org/pdf/1306.5602">pdf</a>, <a href="https://arxiv.org/format/1306.5602">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1748-0221/8/08/P08013">10.1088/1748-0221/8/08/P08013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=AEgIS+Collaboration"> AEgIS Collaboration</a>, <a href="/search/hep-ex?searchtype=author&query=Aghion%2C+S">S. Aghion</a>, <a href="/search/hep-ex?searchtype=author&query=Ahl%C3%A9n%2C+O">O. Ahl茅n</a>, <a href="/search/hep-ex?searchtype=author&query=Amsler%2C+C">C. Amsler</a>, <a href="/search/hep-ex?searchtype=author&query=Ariga%2C+A">A. Ariga</a>, <a href="/search/hep-ex?searchtype=author&query=Ariga%2C+T">T. Ariga</a>, <a href="/search/hep-ex?searchtype=author&query=Belov%2C+A+S">A. S. Belov</a>, <a href="/search/hep-ex?searchtype=author&query=Bonomi%2C+G">G. Bonomi</a>, <a href="/search/hep-ex?searchtype=author&query=Br%C3%A4unig%2C+P">P. Br盲unig</a>, <a href="/search/hep-ex?searchtype=author&query=Bremer%2C+J">J. Bremer</a>, <a href="/search/hep-ex?searchtype=author&query=Brusa%2C+R+S">R. S. Brusa</a>, <a href="/search/hep-ex?searchtype=author&query=Cabaret%2C+L">L. Cabaret</a>, <a href="/search/hep-ex?searchtype=author&query=Canali%2C+C">C. Canali</a>, <a href="/search/hep-ex?searchtype=author&query=Caravita%2C+R">R. Caravita</a>, <a href="/search/hep-ex?searchtype=author&query=Castelli%2C+F">F. Castelli</a>, <a href="/search/hep-ex?searchtype=author&query=Cerchiari%2C+G">G. Cerchiari</a>, <a href="/search/hep-ex?searchtype=author&query=Cialdi%2C+S">S. Cialdi</a>, <a href="/search/hep-ex?searchtype=author&query=Comparat%2C+D">D. Comparat</a>, <a href="/search/hep-ex?searchtype=author&query=Consolati%2C+G">G. Consolati</a>, <a href="/search/hep-ex?searchtype=author&query=Derking%2C+J+H">J. H. Derking</a>, <a href="/search/hep-ex?searchtype=author&query=Di+Domizio%2C+S">S. Di Domizio</a>, <a href="/search/hep-ex?searchtype=author&query=Di+Noto%2C+L">L. Di Noto</a>, <a href="/search/hep-ex?searchtype=author&query=Doser%2C+M">M. Doser</a>, <a href="/search/hep-ex?searchtype=author&query=Dudarev%2C+A">A. Dudarev</a>, <a href="/search/hep-ex?searchtype=author&query=Ereditato%2C+A">A. Ereditato</a> , et al. (46 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1306.5602v1-abstract-short" style="display: inline;"> The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moir茅 deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.5602v1-abstract-full').style.display = 'inline'; document.getElementById('1306.5602v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1306.5602v1-abstract-full" style="display: none;"> The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moir茅 deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the time of flight. Nuclear emulsions can measure the annihilation vertex of antihydrogen atoms with a precision of about 1 - 2 microns r.m.s. We present here results for emulsion detectors operated in vacuum using low energy antiprotons from the CERN antiproton decelerator. We compare with Monte Carlo simulations, and discuss the impact on the AEgIS project. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.5602v1-abstract-full').style.display = 'none'; document.getElementById('1306.5602v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 16 figures, 3 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1209.0060">arXiv:1209.0060</a> <span> [<a href="https://arxiv.org/pdf/1209.0060">pdf</a>, <a href="https://arxiv.org/ps/1209.0060">ps</a>, <a href="https://arxiv.org/format/1209.0060">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.87.015016">10.1103/PhysRevD.87.015016 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Invisible decay of muonium: Tests of the standard model and searches for new physics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Krasnikov%2C+N+V">N. V. Krasnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1209.0060v4-abstract-short" style="display: inline;"> In the Standard Model there are several canonical examples of pure leptonic processes involving the muon, the electron and the corresponding neutrinos which are connected by the crossing symmetry: i) the decay of muon, ii) the inverse muon decay, and iii) the annihilation of a muon and an electron into two neutrinos. Although the first two reactions have been observed and measured since long ago,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.0060v4-abstract-full').style.display = 'inline'; document.getElementById('1209.0060v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1209.0060v4-abstract-full" style="display: none;"> In the Standard Model there are several canonical examples of pure leptonic processes involving the muon, the electron and the corresponding neutrinos which are connected by the crossing symmetry: i) the decay of muon, ii) the inverse muon decay, and iii) the annihilation of a muon and an electron into two neutrinos. Although the first two reactions have been observed and measured since long ago, the third process, resulting in the invisible final state, has never been experimentally tested. It may go either directly, or, at low energies, via the annihilation of a muon and an electron from an atomic bound state, called muonium (M=渭^+e^-). The M\to 谓_渭谓_e decay is expected to be a very rare process, with the branching fraction predicted to be Br(M\to 谓_渭谓_e) = 6.6 10^{-12} with respect to the ordinary muon decay rate. Using the reported experimental results on precision measurements of the positive muon lifetime by the MuLan Collaboration, we set the first limit Br(M \to invisible) < 5.7 10^{-6}, while still leaving a big gap of about six orders of magnitude between this bound and the predictions. To improve substantially the limit, we proposed to perform an experiment dedicated to the sensitive search for the M\to invisible decay. A feasibility study of the experimental setup shows that the sensitivity of the search for this decay mode in branching fraction Br(M\to invisible) at the level of 10^{-12} could be achieved. If the proposed search results in a substantially higher branching fraction than predicted, say Br(M \to invisible) < 10^{-10}, this would unambiguously indicate the presence of new physics. We point out that such a possibility may occur due the muonium-mirror muonium conversion in the mirror matter model. A result in agreement with the Standard Model prediction would be a clean check of the pure leptonic bound state annihilation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1209.0060v4-abstract-full').style.display = 'none'; document.getElementById('1209.0060v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 January, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 September, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published version, but with more detailed description of the experimental setup and modified Fig.2. Refs. added</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Rev. D87 (2013) 015016 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1204.5379">arXiv:1204.5379</a> <span> [<a href="https://arxiv.org/pdf/1204.5379">pdf</a>, <a href="https://arxiv.org/format/1204.5379">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Theory">nucl-th</span> </div> </div> <p class="title is-5 mathjax"> Light Sterile Neutrinos: A White Paper </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Abazajian%2C+K+N">K. N. Abazajian</a>, <a href="/search/hep-ex?searchtype=author&query=Acero%2C+M+A">M. A. Acero</a>, <a href="/search/hep-ex?searchtype=author&query=Agarwalla%2C+S+K">S. K. Agarwalla</a>, <a href="/search/hep-ex?searchtype=author&query=Aguilar-Arevalo%2C+A+A">A. A. Aguilar-Arevalo</a>, <a href="/search/hep-ex?searchtype=author&query=Albright%2C+C+H">C. H. Albright</a>, <a href="/search/hep-ex?searchtype=author&query=Antusch%2C+S">S. Antusch</a>, <a href="/search/hep-ex?searchtype=author&query=Arguelles%2C+C+A">C. A. Arguelles</a>, <a href="/search/hep-ex?searchtype=author&query=Balantekin%2C+A+B">A. B. Balantekin</a>, <a href="/search/hep-ex?searchtype=author&query=Barenboim%2C+G">G. Barenboim</a>, <a href="/search/hep-ex?searchtype=author&query=Barger%2C+V">V. Barger</a>, <a href="/search/hep-ex?searchtype=author&query=Bernardini%2C+P">P. Bernardini</a>, <a href="/search/hep-ex?searchtype=author&query=Bezrukov%2C+F">F. Bezrukov</a>, <a href="/search/hep-ex?searchtype=author&query=Bjaelde%2C+O+E">O. E. Bjaelde</a>, <a href="/search/hep-ex?searchtype=author&query=Bogacz%2C+S+A">S. A. Bogacz</a>, <a href="/search/hep-ex?searchtype=author&query=Bowden%2C+N+S">N. S. Bowden</a>, <a href="/search/hep-ex?searchtype=author&query=Boyarsky%2C+A">A. Boyarsky</a>, <a href="/search/hep-ex?searchtype=author&query=Bravar%2C+A">A. Bravar</a>, <a href="/search/hep-ex?searchtype=author&query=Berguno%2C+D+B">D. Bravo Berguno</a>, <a href="/search/hep-ex?searchtype=author&query=Brice%2C+S+J">S. J. Brice</a>, <a href="/search/hep-ex?searchtype=author&query=Bross%2C+A+D">A. D. Bross</a>, <a href="/search/hep-ex?searchtype=author&query=Caccianiga%2C+B">B. Caccianiga</a>, <a href="/search/hep-ex?searchtype=author&query=Cavanna%2C+F">F. Cavanna</a>, <a href="/search/hep-ex?searchtype=author&query=Chun%2C+E+J">E. J. Chun</a>, <a href="/search/hep-ex?searchtype=author&query=Cleveland%2C+B+T">B. T. Cleveland</a>, <a href="/search/hep-ex?searchtype=author&query=Collin%2C+A+P">A. P. Collin</a> , et al. (162 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1204.5379v1-abstract-short" style="display: inline;"> This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and the latest astrophysical data. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1204.5379v1-abstract-full" style="display: none;"> This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and the latest astrophysical data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.5379v1-abstract-full').style.display = 'none'; document.getElementById('1204.5379v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 April, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2012. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1102.5702">arXiv:1102.5702</a> <span> [<a href="https://arxiv.org/pdf/1102.5702">pdf</a>, <a href="https://arxiv.org/ps/1102.5702">ps</a>, <a href="https://arxiv.org/format/1102.5702">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/S0217751X11054528">10.1142/S0217751X11054528 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Two photon decay of Z' as a probe of Bose symmetry violation at the CERN LHC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Ignatiev%2C+A+Y">A. Yu. Ignatiev</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1102.5702v2-abstract-short" style="display: inline;"> The question if the Bose statistics is broken at the TeV scale is discussed. The decay of a new heavy spin 1 gauge boson Z' into two photons, Z'-> 2 gamma, is forbidden by the Bose statistics among other general principles of quantum field theory (Landau-Yang theorem). We point out that the search for this decay can be effectively used to probe the Bose symmetry violation at the CERN LHC. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1102.5702v2-abstract-full" style="display: none;"> The question if the Bose statistics is broken at the TeV scale is discussed. The decay of a new heavy spin 1 gauge boson Z' into two photons, Z'-> 2 gamma, is forbidden by the Bose statistics among other general principles of quantum field theory (Landau-Yang theorem). We point out that the search for this decay can be effectively used to probe the Bose symmetry violation at the CERN LHC. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.5702v2-abstract-full').style.display = 'none'; document.getElementById('1102.5702v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 October, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 February, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 3 figures. Published version, but with extended introductory discussion</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Mod.Phys. A26 (2011) 4367-4385 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0909.4666">arXiv:0909.4666</a> <span> [<a href="https://arxiv.org/pdf/0909.4666">pdf</a>, <a href="https://arxiv.org/ps/0909.4666">ps</a>, <a href="https://arxiv.org/format/0909.4666">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1134/S1063778810070094">10.1134/S1063778810070094 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental search for radiative decays of the pentaquark baryon 螛^+(1540) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barmin%2C+V+V">V. V. Barmin</a>, <a href="/search/hep-ex?searchtype=author&query=Asratyan%2C+A+E">A. E. Asratyan</a>, <a href="/search/hep-ex?searchtype=author&query=Borisov%2C+V+S">V. S. Borisov</a>, <a href="/search/hep-ex?searchtype=author&query=Curceanu%2C+C">C. Curceanu</a>, <a href="/search/hep-ex?searchtype=author&query=Davidenko%2C+G+V">G. V. Davidenko</a>, <a href="/search/hep-ex?searchtype=author&query=Dolgolenko%2C+A+G">A. G. Dolgolenko</a>, <a href="/search/hep-ex?searchtype=author&query=Guaraldo%2C+C">C. Guaraldo</a>, <a href="/search/hep-ex?searchtype=author&query=Kubantsev%2C+M+A">M. A. Kubantsev</a>, <a href="/search/hep-ex?searchtype=author&query=Larin%2C+I+F">I. F. Larin</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Shebanov%2C+V+A">V. A. Shebanov</a>, <a href="/search/hep-ex?searchtype=author&query=Shishov%2C+N+N">N. N. Shishov</a>, <a href="/search/hep-ex?searchtype=author&query=Sokolov%2C+L+I">L. I. Sokolov</a>, <a href="/search/hep-ex?searchtype=author&query=Tumanov%2C+G+K">G. K. Tumanov</a>, <a href="/search/hep-ex?searchtype=author&query=Verebryusov%2C+V+S">V. S. Verebryusov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0909.4666v1-abstract-short" style="display: inline;"> The data on the reactions K^+Xe --> K^0 纬X and K^+Xe --> K^+ 纬X, obtained with the bubble chamber DIANA, have been analyzed for possible radiative decays of the 螛^+(1540) baryon: 螛^+ --> K^0 p 纬and 螛^+ --> K^+ n 纬. No signals have been observed, and we derive the upper limits 螕(螛^+ --> K^0 p 纬) / 螕(螛^+ --> K^0 p) < 0.032 and 螕(螛^+ --> K^+ n 纬) / 螕(螛^+ --> K^+ n) < 0.041 which, using our previous… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.4666v1-abstract-full').style.display = 'inline'; document.getElementById('0909.4666v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0909.4666v1-abstract-full" style="display: none;"> The data on the reactions K^+Xe --> K^0 纬X and K^+Xe --> K^+ 纬X, obtained with the bubble chamber DIANA, have been analyzed for possible radiative decays of the 螛^+(1540) baryon: 螛^+ --> K^0 p 纬and 螛^+ --> K^+ n 纬. No signals have been observed, and we derive the upper limits 螕(螛^+ --> K^0 p 纬) / 螕(螛^+ --> K^0 p) < 0.032 and 螕(螛^+ --> K^+ n 纬) / 螕(螛^+ --> K^+ n) < 0.041 which, using our previous measurement of 螕(螛^+ --> KN) = (0.39+-0.10) MeV, translate to 螕(螛^+ --> K^0 p 纬) < 8 keV and 螕(螛^+ --> K^+ n 纬) < 11 keV at 90% confidence level. We have also measured the cross sections of K^+ -induced reactions involving emission of a neutral pion: 蟽(K^+n --> K^0 p 蟺^0) = (68+-18) \mub and 蟽(K^+N --> K^+ N 蟺^0) = (30+-8) \mub for incident K^+ momentum of 640 MeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.4666v1-abstract-full').style.display = 'none'; document.getElementById('0909.4666v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 September, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2009. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Atom.Nucl.73:1164-1167,2010 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0909.4183">arXiv:0909.4183</a> <span> [<a href="https://arxiv.org/pdf/0909.4183">pdf</a>, <a href="https://arxiv.org/ps/0909.4183">ps</a>, <a href="https://arxiv.org/format/0909.4183">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1134/S1063778810070100">10.1134/S1063778810070100 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Formation of a narrow baryon resonance with positive strangeness in K^+ collisions with Xe nuclei </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barmin%2C+V+V">V. V. Barmin</a>, <a href="/search/hep-ex?searchtype=author&query=Asratyan%2C+A+E">A. E. Asratyan</a>, <a href="/search/hep-ex?searchtype=author&query=Borisov%2C+V+S">V. S. Borisov</a>, <a href="/search/hep-ex?searchtype=author&query=Curceanu%2C+C">C. Curceanu</a>, <a href="/search/hep-ex?searchtype=author&query=Davidenko%2C+G+V">G. V. Davidenko</a>, <a href="/search/hep-ex?searchtype=author&query=Dolgolenko%2C+A+G">A. G. Dolgolenko</a>, <a href="/search/hep-ex?searchtype=author&query=Guaraldo%2C+C">C. Guaraldo</a>, <a href="/search/hep-ex?searchtype=author&query=Kubantsev%2C+M+A">M. A. Kubantsev</a>, <a href="/search/hep-ex?searchtype=author&query=Larin%2C+I+F">I. F. Larin</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Shebanov%2C+V+A">V. A. Shebanov</a>, <a href="/search/hep-ex?searchtype=author&query=Shishov%2C+N+N">N. N. Shishov</a>, <a href="/search/hep-ex?searchtype=author&query=Sokolov%2C+L+I">L. I. Sokolov</a>, <a href="/search/hep-ex?searchtype=author&query=Tumanov%2C+G+K">G. K. Tumanov</a>, <a href="/search/hep-ex?searchtype=author&query=Verebryusov%2C+V+S">V. S. Verebryusov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0909.4183v1-abstract-short" style="display: inline;"> The data on the charge-exchange reaction K^+Xe --> K^0 p Xe, obtained with the bubble chamber DIANA, are reanalyzed using increased statistics and updated selections. Our previous evidence for formation of a narrow pK^0 resonance with mass near 1538 MeV is confirmed and reinforced. The statistical significance of the signal reaches some 8蟽(6蟽) when estimated as S/\sqrt{B} (S/\sqrt{B+S}). The mas… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.4183v1-abstract-full').style.display = 'inline'; document.getElementById('0909.4183v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0909.4183v1-abstract-full" style="display: none;"> The data on the charge-exchange reaction K^+Xe --> K^0 p Xe, obtained with the bubble chamber DIANA, are reanalyzed using increased statistics and updated selections. Our previous evidence for formation of a narrow pK^0 resonance with mass near 1538 MeV is confirmed and reinforced. The statistical significance of the signal reaches some 8蟽(6蟽) when estimated as S/\sqrt{B} (S/\sqrt{B+S}). The mass and intrinsic width of the 螛^+ baryon are measured as m = (1538+-2) MeV and 螕= (0.39+-0.10) MeV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.4183v1-abstract-full').style.display = 'none'; document.getElementById('0909.4183v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2009. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Atom.Nucl.73:1168-1175,2010 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/hep-ex/0603017">arXiv:hep-ex/0603017</a> <span> [<a href="https://arxiv.org/pdf/hep-ex/0603017">pdf</a>, <a href="https://arxiv.org/ps/hep-ex/0603017">ps</a>, <a href="https://arxiv.org/format/hep-ex/0603017">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1134/S106377880701005X">10.1134/S106377880701005X <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Further evidence for formation of a narrow baryon resonance with positive strangeness in K+ collisions with Xe nuclei </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barmin%2C+V+V">V. V. Barmin</a>, <a href="/search/hep-ex?searchtype=author&query=Asratyan%2C+A+E">A. E. Asratyan</a>, <a href="/search/hep-ex?searchtype=author&query=Borisov%2C+V+S">V. S. Borisov</a>, <a href="/search/hep-ex?searchtype=author&query=Curceanu%2C+C">C. Curceanu</a>, <a href="/search/hep-ex?searchtype=author&query=Davidenko%2C+G+V">G. V. Davidenko</a>, <a href="/search/hep-ex?searchtype=author&query=Dolgolenko%2C+A+G">A. G. Dolgolenko</a>, <a href="/search/hep-ex?searchtype=author&query=Guaraldo%2C+C">C. Guaraldo</a>, <a href="/search/hep-ex?searchtype=author&query=Kubantsev%2C+M+A">M. A. Kubantsev</a>, <a href="/search/hep-ex?searchtype=author&query=Larin%2C+I+F">I. F. Larin</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Shebanov%2C+V+A">V. A. Shebanov</a>, <a href="/search/hep-ex?searchtype=author&query=Shishov%2C+N+N">N. N. Shishov</a>, <a href="/search/hep-ex?searchtype=author&query=Sokolov%2C+L+I">L. I. Sokolov</a>, <a href="/search/hep-ex?searchtype=author&query=Tumanov%2C+G+K">G. K. Tumanov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="hep-ex/0603017v2-abstract-short" style="display: inline;"> We have continued our investigation of the charge-exchange reaction K^+ Xe --> K^0 p Xe' in the bubble chamber DIANA. In agreement with our previous results based on part of the present statistics, formation of a narrow p K^0 resonance with mass of 1537+-2 MeV/c^2 is observed in the elementary transition K^+ n --> K^0 p on a neutron bound in the Xenon nucleus. Visible width of the peak is consis… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('hep-ex/0603017v2-abstract-full').style.display = 'inline'; document.getElementById('hep-ex/0603017v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="hep-ex/0603017v2-abstract-full" style="display: none;"> We have continued our investigation of the charge-exchange reaction K^+ Xe --> K^0 p Xe' in the bubble chamber DIANA. In agreement with our previous results based on part of the present statistics, formation of a narrow p K^0 resonance with mass of 1537+-2 MeV/c^2 is observed in the elementary transition K^+ n --> K^0 p on a neutron bound in the Xenon nucleus. Visible width of the peak is consistent with being entirely due to instrumental resolution and allows to place an upper limit on its intrinsic width: 螕< 9 MeV/c^2. A more precise estimate of the resonance intrinsic width, 螕= 0.36+-0.11 MeV/c^2, is obtained from the ratio between the numbers of resonant and non-resonant charge-exchange events. The signal is observed in a restricted interval of incident K^+ momentum, that is consistent with smearing of a narrow p K^0 resonance by Fermi motion of the target neutron. Statistical significance of the signal is some 7.3, 5.3, and 4.3 standard deviations for the estimators S/sqrt{B}, S/sqrt{S+B}, and S/sqrt{S+2B}, respectively. This observation confirms and reinforces our earlier results, and offers strong evidence for formation of a pentaquark baryon with positive strangeness in the charge-exchange reaction K^+ n --> K^0 p on a bound neutron. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('hep-ex/0603017v2-abstract-full').style.display = 'none'; document.getElementById('hep-ex/0603017v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 April, 2006; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 March, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2006. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 8 figures, some chenges in text and references, more precise estimate of Theta(1540) to add, submitted to Phys.Atom.Nucl(Yad.Fiz.)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Atom.Nucl. 70 (2007) 35-43 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/hep-ex/0304040">arXiv:hep-ex/0304040</a> <span> [<a href="https://arxiv.org/pdf/hep-ex/0304040">pdf</a>, <a href="https://arxiv.org/ps/hep-ex/0304040">ps</a>, <a href="https://arxiv.org/format/hep-ex/0304040">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1134/1.1611587">10.1134/1.1611587 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of a baryon resonance with positive strangeness in K+ collisions with Xe nuclei </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Barmin%2C+V+V">V. V. Barmin</a>, <a href="/search/hep-ex?searchtype=author&query=Borisov%2C+V+S">V. S. Borisov</a>, <a href="/search/hep-ex?searchtype=author&query=Davidenko%2C+G+V">G. V. Davidenko</a>, <a href="/search/hep-ex?searchtype=author&query=Dolgolenko%2C+A+G">A. G. Dolgolenko</a>, <a href="/search/hep-ex?searchtype=author&query=Guaraldo%2C+C">C. Guaraldo</a>, <a href="/search/hep-ex?searchtype=author&query=Larin%2C+I+F">I. F. Larin</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a>, <a href="/search/hep-ex?searchtype=author&query=Petrascu%2C+C">C. Petrascu</a>, <a href="/search/hep-ex?searchtype=author&query=Shebanov%2C+V+A">V. A. Shebanov</a>, <a href="/search/hep-ex?searchtype=author&query=Shishov%2C+N+N">N. N. Shishov</a>, <a href="/search/hep-ex?searchtype=author&query=Sokolov%2C+L+I">L. I. Sokolov</a>, <a href="/search/hep-ex?searchtype=author&query=Tumanov%2C+G+K">G. K. Tumanov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="hep-ex/0304040v4-abstract-short" style="display: inline;"> The status of our investigation of low-energy $K^+$Xe collisions in the Xenon bubble chamber DIANA is reported. In the charge-exchange reaction $K^+Xe \to K^0 p Xe'$ the spectrum of $K^0 p$ effective mass shows a resonant enhancement with $M = 1539 \pm 2$ MeV/c$^2$ and $螕\le 9 MeV/c$^2$. The statistical significance of the enhancement is near $4.4蟽$. The mass and width of the observed resonance… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('hep-ex/0304040v4-abstract-full').style.display = 'inline'; document.getElementById('hep-ex/0304040v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="hep-ex/0304040v4-abstract-full" style="display: none;"> The status of our investigation of low-energy $K^+$Xe collisions in the Xenon bubble chamber DIANA is reported. In the charge-exchange reaction $K^+Xe \to K^0 p Xe'$ the spectrum of $K^0 p$ effective mass shows a resonant enhancement with $M = 1539 \pm 2$ MeV/c$^2$ and $螕\le 9 MeV/c$^2$. The statistical significance of the enhancement is near $4.4蟽$. The mass and width of the observed resonance are consistent with expectations for the lightest member of the anti-decuplet of exotic pentaquark baryons, as predicted in the framework of the chiral soliton model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('hep-ex/0304040v4-abstract-full').style.display = 'none'; document.getElementById('hep-ex/0304040v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 September, 2003; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 April, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2003. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Atom.Nucl.66:1715-1718,2003; Yad.Fiz.66:1763-1766,2003 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/hep-ph/0106302">arXiv:hep-ph/0106302</a> <span> [<a href="https://arxiv.org/pdf/hep-ph/0106302">pdf</a>, <a href="https://arxiv.org/ps/hep-ph/0106302">ps</a>, <a href="https://arxiv.org/format/hep-ph/0106302">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/S0217732302007855">10.1142/S0217732302007855 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing lepton flavour violation in $谓_渭 + N \to 蟿+ ...$ scattering and $渭\to tau$ conversion on nucleons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Gninenko%2C+S+N">S. N. Gninenko</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Krasnikov%2C+N+V">N. V. Krasnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Matveev%2C+V+A">V. A. Matveev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="hep-ph/0106302v1-abstract-short" style="display: inline;"> We study lepton flavour-violating interactions which could result in the $蟿$-lepton production in the $谓_渭N$ scattering or in $渭\to 蟿$ conversion on nucleons at high energies. Phenomenological bounds on the strength of $\bar蟿谓_渭\bar{q}q^{'}$ interactions are extracted from the combined result of the NOMAD and CHORUS experiments on searching for $谓_渭 - 谓_蟿$ oscillations. Some of these bounds supe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('hep-ph/0106302v1-abstract-full').style.display = 'inline'; document.getElementById('hep-ph/0106302v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="hep-ph/0106302v1-abstract-full" style="display: none;"> We study lepton flavour-violating interactions which could result in the $蟿$-lepton production in the $谓_渭N$ scattering or in $渭\to 蟿$ conversion on nucleons at high energies. Phenomenological bounds on the strength of $\bar蟿谓_渭\bar{q}q^{'}$ interactions are extracted from the combined result of the NOMAD and CHORUS experiments on searching for $谓_渭 - 谓_蟿$ oscillations. Some of these bounds supersede limits from rare decays. We also propose a ``missing energy'' type experiment searching for $渭- 蟿$ conversion on nucleons. The experiment can be performed at a present accelerator or at a future neutrino factory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('hep-ph/0106302v1-abstract-full').style.display = 'none'; document.getElementById('hep-ph/0106302v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 June, 2001; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2001. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> INR-RAS/2001-024 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Mod.Phys.Lett.A17:1407,2002 </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 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