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Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector

Measurements of four-particle cumulants $c_n\{4\}$ for $n=1,2,3,4$ are presented using 470 $\mu\text{b}^{-1}$ of Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of single harmonics $p(v_n)$....

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Autor principal: Zhou, Mingliang
Lenguaje:eng
Publicado: 2018
Materias:
Acceso en línea:https://dx.doi.org/10.1016/j.nuclphysa.2018.09.012
http://cds.cern.ch/record/2630827
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author Zhou, Mingliang
author_facet Zhou, Mingliang
author_sort Zhou, Mingliang
collection CERN
description Measurements of four-particle cumulants $c_n\{4\}$ for $n=1,2,3,4$ are presented using 470 $\mu\text{b}^{-1}$ of Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of single harmonics $p(v_n)$. For the first time, a negative $c_1\{4\}$ is observed. The $c_4\{4\}$ is found to be negative in central collisions but changes sign around $20-25\%$ centrality and increases for more peripheral collisions. This behavior is consistent with a nonlinear contribution to $v_4$ that is proportional to $v_2^2$. $c_2\{4\}$ and $c_3\{\{4\}\}$ are calculated using two reference event classes in order to investigate the influence of volume fluctuations on the flow fluctuations. Over most of the centrality range, $c_2\{4\}$ and $c_3\{4\}$ are found to be negative, while in the ultra-central collisions, $c_2\{4\}$ changes sign and becomes positive, suggesting a deviation from Gaussian behavior in the event-by-event fluctuation of $v_2$. The magnitudes of the sign change are also found to be dependent of the event class definition.
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spelling cern-26308272022-02-02T15:26:02Zdoi:10.1016/j.nuclphysa.2018.09.012http://cds.cern.ch/record/2630827engZhou, MingliangFlow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detectorParticle Physics - ExperimentMeasurements of four-particle cumulants $c_n\{4\}$ for $n=1,2,3,4$ are presented using 470 $\mu\text{b}^{-1}$ of Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of single harmonics $p(v_n)$. For the first time, a negative $c_1\{4\}$ is observed. The $c_4\{4\}$ is found to be negative in central collisions but changes sign around $20-25\%$ centrality and increases for more peripheral collisions. This behavior is consistent with a nonlinear contribution to $v_4$ that is proportional to $v_2^2$. $c_2\{4\}$ and $c_3\{\{4\}\}$ are calculated using two reference event classes in order to investigate the influence of volume fluctuations on the flow fluctuations. Over most of the centrality range, $c_2\{4\}$ and $c_3\{4\}$ are found to be negative, while in the ultra-central collisions, $c_2\{4\}$ changes sign and becomes positive, suggesting a deviation from Gaussian behavior in the event-by-event fluctuation of $v_2$. The magnitudes of the sign change are also found to be dependent of the event class definition.ATL-PHYS-PROC-2018-070oai:cds.cern.ch:26308272018-07-13
spellingShingle Particle Physics - Experiment
Zhou, Mingliang
Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector
title Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector
title_full Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector
title_fullStr Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector
title_full_unstemmed Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector
title_short Flow fluctuations in Pb+Pb collisions at $\sqrt{s_\text{NN}}=5.02$ TeV with the ATLAS detector
title_sort flow fluctuations in pb+pb collisions at $\sqrt{s_\text{nn}}=5.02$ tev with the atlas detector
topic Particle Physics - Experiment
url https://dx.doi.org/10.1016/j.nuclphysa.2018.09.012
http://cds.cern.ch/record/2630827
work_keys_str_mv AT zhoumingliang flowfluctuationsinpbpbcollisionsatsqrtstextnn502tevwiththeatlasdetector