<?xml version="1.0" encoding="UTF-8"?> <rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/"> <channel> <title>CERN Document Server</title> <link>https://cds.cern.ch</link> <description>CERN Document Server latest documents</description> <language>en</language> <pubDate>Sun, 24 Nov 2024 14:23:50 GMT</pubDate> <category></category> <generator>Invenio 1.1.3.1106-62468</generator> <ttl>360</ttl> <atom:link rel="self" href="/rss?f=author&amp;ln=bg&amp;p=Lamb%2C+Elleanor" /> <opensearch:totalResults>4</opensearch:totalResults> <opensearch:startIndex>1</opensearch:startIndex> <opensearch:itemsPerPage>25</opensearch:itemsPerPage> <image> <url>https://cds.cern.ch/img/site_logo_rss.png</url> <title>CERN Document Server</title> <link>https://cds.cern.ch</link> </image> <atom:link rel="search" href="https://cds.cern.ch/opensearchdescription" type="application/opensearchdescription+xml" title="Content Search" /> <textInput> <title>Search </title> <description>Search this site:</description> <name>p</name> <link>https://cds.cern.ch/search</link> </textInput> <item> <title>Measurements of beam correlations induced via coupled resonance crossing in the CERN PSB</title> <link>https://cds.cern.ch/record/2913149</link> <description>Beam profile measurements in the LHC and its injector complex show heavy tails in both transverse planes. From standard profile measurements, it is not possible to determineif the underlying phase space distribution is statistically independent. A measurement campaign in the CERN PSB was carried out to introduce cross-plane dependence in bunched beams in controlled conditions, in view of characterizing the LHC operational beam distributions. The results of the measurement campaign demonstrate how heavy tails can be created via coupled resonance excitation of the lattice in the presence of space charge, in accordance with predictions from the fixed line theory. The coupled resonance introduces dependence between the different planes, which persists after the resonance excitation is removed.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lamb, Elleanor</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Asvesta, Foteini</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Franchetti, Giuliano</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Sterbini, Guido</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bartosik, Hannes</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Seidel, Mike</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Albright, Simon</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Prebibaj, Tirsi</dc:creator> <pubDate>Fri, 11 Oct 2024 05:10:26 GMT</pubDate> <guid>https://cds.cern.ch/record/2913149</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2913149/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Luminosity effects due to dependent heavy-tailed beams</title> <link>https://cds.cern.ch/record/2912366</link> <description>The luminosity of particle colliders depends, among other parameters, on the transverse profiles of the colliding beams. At the LHC at CERN, heavy-tailed transverse beam distributions are typically observed in routine operation. The luminosity is usually modelled with the assumption that the 饾懃-饾懄 planes are independent (i.e. statistically uncorrelated particle distributions between the planes) in each beam. Analytical calculations show that the solution of inverting 1D heavy-tailed beam profiles to transverse 4D phase-space distributions is not unique. For a given transverse beam profile, the distributions can be dependent (i.e. statistically correlated) or independent in the transverse planes, even in the absence of machine coupling. In this work, the effect of transverse 饾懃-饾懄 dependence of the 4D phase space distribution on the luminosity of a particle collider is evaluated for heavy-tailed beams.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lamb, Elleanor</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Sterbini, Guido</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bartosik, Hannes</dc:creator> <pubDate>Fri, 04 Oct 2024 06:52:50 GMT</pubDate> <guid>https://cds.cern.ch/record/2912366</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2912366/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Numerical methods for emittance computation from luminosity</title> <link>https://cds.cern.ch/record/2912362</link> <description>The beam transverse emittances play a critical role in high-energy colliders. Various measurement techniques are employed to measure them. In particular, the so-called luminosity emittance scans (or Van der Meer scans) are used in order to evaluate the convoluted beam emittances. This method assumes different emittances in the two planes but identical emittances in the two beams. In this paper, we propose an approach to remove this constraint. After having presented the new measurement protocol, we will discuss its potential and limits, including the statistical measurement error of the luminosity value as obtained from numerical studies.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Rufolo, Matteo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Fornara, Andrea</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lamb, Elleanor</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Sterbini, Guido</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Giacomel, Lorenzo</dc:creator> <pubDate>Fri, 04 Oct 2024 06:52:46 GMT</pubDate> <guid>https://cds.cern.ch/record/2912362</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2912362/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Measurement of Transverse Statistical Dependence for Non-Gaussian Beam Distributions via Resonances in the CERN PSB</title> <link>https://cds.cern.ch/record/2901221</link> <description>This work addresses the origins and the effects of the statistical dependence in non-Gaussian beam distributions with the ultimate goal to identify the most representative case for tracking simulations across the CERN accelerator complex. Starting from the observation that non-Gaussian heavy-tailed transverse beam profiles can be reconstructed from 4D phase space distributions under two different conditions (statistical independence or dependence in the x-y plane), we consider space charge dominated beams interacting with the lattice nonlinear resonances to perform measurements to study the mechanisms that lead to non-Gaussian distributions. Finally, we explore the beam dynamics implications of the above hypotheses in terms of dependent loss processes across the transverse planes.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lamb, Elleanor</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Asvesta, Foteini</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bartosik, Hannes</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Sterbini, Guido</dc:creator> <pubDate>Tue, 18 Jun 2024 05:48:54 GMT</pubDate> <guid>https://cds.cern.ch/record/2901221</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2901221/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> </channel> </rss>