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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/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/2305.09015">arXiv:2305.09015</a> <span> [<a href="https://arxiv.org/pdf/2305.09015">pdf</a>, <a href="https://arxiv.org/format/2305.09015">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"> Probing hidden sectors with a muon beam: implication of spin-0 dark matter mediators for muon $(g-2)$ anomaly and validity of the Weisz盲cker-Williams approach </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Sieber%2C+H">H. Sieber</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=Voronchikhin%2C+I+V">I. V. Voronchikhin</a>, <a href="/search/hep-ex?searchtype=author&query=Crivelli%2C+P">P. Crivelli</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=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=Molina-Bueno%2C+L">L. Molina-Bueno</a>, <a href="/search/hep-ex?searchtype=author&query=Sekatskii%2C+S+K">S. K. Sekatskii</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="2305.09015v2-abstract-short" style="display: inline;"> In addition to vector ($V$) type new particles extensively discussed previously, both CP-even ($S$) and CP-odd ($P$) spin-0 Dark Matter (DM) mediators can couple to muons and be produced in the bremsstrahlung reaction $渭^- + N \rightarrow 渭^- + N + S(P)$. Their possible subsequent invisible decay into a pair of Dirac DM particles, $S(P) \to 蠂\overline蠂$, can be detected in fixed target experiments… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.09015v2-abstract-full').style.display = 'inline'; document.getElementById('2305.09015v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.09015v2-abstract-full" style="display: none;"> In addition to vector ($V$) type new particles extensively discussed previously, both CP-even ($S$) and CP-odd ($P$) spin-0 Dark Matter (DM) mediators can couple to muons and be produced in the bremsstrahlung reaction $渭^- + N \rightarrow 渭^- + N + S(P)$. Their possible subsequent invisible decay into a pair of Dirac DM particles, $S(P) \to 蠂\overline蠂$, can be detected in fixed target experiments through missing energy signature. In this paper, we focus on the case of experiments using high-energy muon beams. For this reason, we derive the differential cross-sections involved using the phase space Weisz盲cker-Williams approximation and compare them to the exact-tree-level calculations. The formalism derived can be applied in various experiments that could observe muon-spin-0 DM interactions. This can happen in present and future proton beam-dump experiments such as NA62, SHIP, HIKE, and SHADOWS; in muon fixed target experiments as NA64$渭$, MUoNE and M3; in neutrino experiments using powerful proton beams such as DUNE. In particular, we focus on the NA64$渭$ experiment case, which uses a 160 GeV muon beam at the CERN Super Proton Synchrotron accelerator. We compute the derived cross-sections, the resulting signal yields and we discuss the experiment projected sensitivity to probe the relic DM parameter space and the $(g-2)_渭$ anomaly favoured region considering $10^{12}$ and $10^{13}$ muons on target. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.09015v2-abstract-full').style.display = 'none'; document.getElementById('2305.09015v2-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 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">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 9 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/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/2110.15111">arXiv:2110.15111</a> <span> [<a href="https://arxiv.org/pdf/2110.15111">pdf</a>, <a href="https://arxiv.org/format/2110.15111">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.105.052006">10.1103/PhysRevD.105.052006 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Prospects in the search for a new light $Z'$ boson with the NA64$渭$ experiment at the CERN SPS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Sieber%2C+H">H. Sieber</a>, <a href="/search/hep-ex?searchtype=author&query=Banerjee%2C+D">D. Banerjee</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=Gninenko%2C+S+N">S. N. Gninenko</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=Poliakov%2C+V">V. Poliakov</a>, <a href="/search/hep-ex?searchtype=author&query=Bueno%2C+L+M">L. Molina Bueno</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="2110.15111v1-abstract-short" style="display: inline;"> A light $Z'$ vector boson coupled to the second and third lepton generations through $L_渭-L_蟿$ current with mass below 200 MeV provides a very viable explanation in terms of new physics to the recently confirmed $(g-2)_渭$ anomaly. This boson can be produced in the bremsstrahlung reaction $渭N \rightarrow 渭N Z'$ after a high energy muon beam collides with a target. NA64$渭$ is a fixed-target experime… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.15111v1-abstract-full').style.display = 'inline'; document.getElementById('2110.15111v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.15111v1-abstract-full" style="display: none;"> A light $Z'$ vector boson coupled to the second and third lepton generations through $L_渭-L_蟿$ current with mass below 200 MeV provides a very viable explanation in terms of new physics to the recently confirmed $(g-2)_渭$ anomaly. This boson can be produced in the bremsstrahlung reaction $渭N \rightarrow 渭N Z'$ after a high energy muon beam collides with a target. NA64$渭$ is a fixed-target experiment using a 160 GeV muon beam from the CERN Super Proton Synchrotron accelerator looking for the $Z'$ production and its subsequent decays, $Z'\rightarrow invisible$. In this paper, we present the study of the NA64$渭$ sensitivity to search for such a $Z'$. This includes a realistic beam simulation, the detailed detectors description and a discussion about the main potential background sources. A pilot run is scheduled in order to validate the simulation results. If those are confirmed, NA64$渭$ will be able to explore all the remaining phase space which could provide an explanation for the $g-2$ muon anomaly. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.15111v1-abstract-full').style.display = 'none'; document.getElementById('2110.15111v1-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> 28 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.13297">arXiv:2107.13297</a> <span> [<a href="https://arxiv.org/pdf/2107.13297">pdf</a>, <a href="https://arxiv.org/format/2107.13297">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.104.076012">10.1103/PhysRevD.104.076012 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing Hidden Sectors with a muon beam: Total and differential cross-sections for vector boson production in muon bremsstrahlung </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Sieber%2C+H">H. Sieber</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=Crivelli%2C+P">P. Crivelli</a>, <a href="/search/hep-ex?searchtype=author&query=Kirsanov%2C+M+M">M. M. Kirsanov</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="2107.13297v2-abstract-short" style="display: inline;"> Vector bosons, such as Dark Photon $A'$ or $Z'$, can couple to muons and be produced in the bremsstrahlung reaction $渭^- + N \rightarrow 渭^- + N + A'(Z')$. Their possible subsequent invisible decay can be detected in fixed target experiments through missing energy/momentum signature. In such experiments, not only is the energy transfer to $A'(Z')$ important, but also the recoil muon angle… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13297v2-abstract-full').style.display = 'inline'; document.getElementById('2107.13297v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.13297v2-abstract-full" style="display: none;"> Vector bosons, such as Dark Photon $A'$ or $Z'$, can couple to muons and be produced in the bremsstrahlung reaction $渭^- + N \rightarrow 渭^- + N + A'(Z')$. Their possible subsequent invisible decay can be detected in fixed target experiments through missing energy/momentum signature. In such experiments, not only is the energy transfer to $A'(Z')$ important, but also the recoil muon angle $蠄_{渭'}$. In this paper, we derive the total and the double differential cross-sections involved in this process using the phase space Weisz盲cker-Williams and improved Weisz盲cker-Williams approximations, as well as using exact-tree-level calculations. As an example, we compare the derived cross-sections and resulting signal yields in the NA64$渭$ experiment that uses a 160 GeV muon beam at the CERN Super Proton Synchrotron accelerator. We also discuss its impact on the NA64$渭$ expected sensitivity to explore the $(g-2)_渭$ anomaly favoured region with a $Z'$ boson considering $10^{12}$ muons accumulated on target. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13297v2-abstract-full').style.display = 'none'; document.getElementById('2107.13297v2-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 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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/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/2011.12871">arXiv:2011.12871</a> <span> [<a href="https://arxiv.org/pdf/2011.12871">pdf</a>, <a href="https://arxiv.org/format/2011.12871">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/10.1007/JHEP03(2021)143">10.1007/JHEP03(2021)143 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Examining axion-like particles with superconducting radio-frequency cavity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Salnikov%2C+D">Dmitry Salnikov</a>, <a href="/search/hep-ex?searchtype=author&query=Satunin%2C+P">Petr Satunin</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=Fitkevich%2C+M">Maxim Fitkevich</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="2011.12871v3-abstract-short" style="display: inline;"> We address production of massive axion-like particles by two electromagnetic modes inside a superconducting radio-frequency (SRF) cylindrical cavity. We discuss in detail the choice of pump modes and cavity design. We numerically compute time-averaged energy density of produced axion field for various cavity modes and wide range of axion masses. This allows us to estimate optimal conditions for ax… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.12871v3-abstract-full').style.display = 'inline'; document.getElementById('2011.12871v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.12871v3-abstract-full" style="display: none;"> We address production of massive axion-like particles by two electromagnetic modes inside a superconducting radio-frequency (SRF) cylindrical cavity. We discuss in detail the choice of pump modes and cavity design. We numerically compute time-averaged energy density of produced axion field for various cavity modes and wide range of axion masses. This allows us to estimate optimal conditions for axion production within a cavity. In addition, we consider photon regeneration process initiated by produced axion field in a screened radio-frequency cavity and derive constraints in parameter space $(g_{a纬纬},\ m_a)$ for different choice of pump modes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.12871v3-abstract-full').style.display = 'none'; document.getElementById('2011.12871v3-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 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">22 pages, 6 figures, 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> INR-TH-2020-044 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> JHEP 03 (2021) 143 </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/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/1604.08432">arXiv:1604.08432</a> <span> [<a href="https://arxiv.org/pdf/1604.08432">pdf</a>, <a href="https://arxiv.org/format/1604.08432">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.94.095025">10.1103/PhysRevD.94.095025 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Missing energy signature from invisible decays of dark photons at the CERN SPS </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=Kirsanov%2C+M+M">M. M. Kirsanov</a>, <a href="/search/hep-ex?searchtype=author&query=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</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="1604.08432v2-abstract-short" style="display: inline;"> The dark photon ($A'$) production through the mixing with the bremsstrahlung photon from the electron scattering off nuclei can be accompanied by the dominant invisible $A'$ decay into dark-sector particles. In this work we discuss the missing energy signature of this process in the experiment NA64 aiming at the search for $A'\to invisible$ decays with a high-energy electron beam at the CERN SPS.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.08432v2-abstract-full').style.display = 'inline'; document.getElementById('1604.08432v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.08432v2-abstract-full" style="display: none;"> The dark photon ($A'$) production through the mixing with the bremsstrahlung photon from the electron scattering off nuclei can be accompanied by the dominant invisible $A'$ decay into dark-sector particles. In this work we discuss the missing energy signature of this process in the experiment NA64 aiming at the search for $A'\to invisible$ decays with a high-energy electron beam at the CERN SPS. We show the distinctive distributions of variables that can be used to distinguish the $A'\to invisible$ signal from background. The results of the detailed simulation of the detector response for the events with and without $A'$ emission are presented. The efficiency of the signal event selection is estimated. It is used to evaluate the sensitivity of the experiment and show that it allows to probe the still unexplored area of the mixing strength $10^{-6}\lesssim 蔚\lesssim 10^{-2}$ and masses up to $M_{A'} \lesssim 1$ GeV. The results obtained are compared with the results from other calculations. In the case of the signal observation, a possibility of extraction of the parameters $M_{A'}$ and $蔚$ by using the missing energy spectrum shape is discussed. We consider as an example the $A'$ with the mass 16.7 MeV and mixing $蔚\lesssim 10^{-3}$, which can explain an excess of events recently observed in nuclear transitions of an excited state of $^8$Be. We show that if such $A'$ exists its invisible decay can be observed in NA64 within a month of running, while data accumulated during a few months would allow also to determine the $蔚$ and $M_{A'}$ parameters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.08432v2-abstract-full').style.display = 'none'; document.getElementById('1604.08432v2-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> 12 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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, 15 figures. Revised version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. D 94, 095025 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1411.6171">arXiv:1411.6171</a> <span> [<a href="https://arxiv.org/pdf/1411.6171">pdf</a>, <a href="https://arxiv.org/format/1411.6171">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.91.035005">10.1103/PhysRevD.91.035005 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Collider signatures of Hylogenesis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/hep-ex?searchtype=author&query=Demidov%2C+S+V">S. V. Demidov</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=Kirpichnikov%2C+D+V">D. V. Kirpichnikov</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="1411.6171v2-abstract-short" style="display: inline;"> We consider collider signatures of the hylogenesis --- a variant of antibaryonic dark matter model. We obtain bounds on the model parameters from results of the first LHC run. Also we suggest several new channels relevant for probing the antibaryonic dark matter at LHC. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1411.6171v2-abstract-full" style="display: none;"> We consider collider signatures of the hylogenesis --- a variant of antibaryonic dark matter model. We obtain bounds on the model parameters from results of the first LHC run. Also we suggest several new channels relevant for probing the antibaryonic dark matter at LHC. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.6171v2-abstract-full').style.display = 'none'; document.getElementById('1411.6171v2-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 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 November, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">5 pages, 5 figures, replaced with journal version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> INR-TH/2014-027 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. D 91, 035005 (2015) </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 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><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 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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