Aaboud, M;
Aad, G;
Abbott, B;
Abbott, DC;
Abdinov, O;
Abed Abud, A;
Abhayasinghe, DK;
... Araque, JP; + view all
(2020)
Fluctuations of anisotropic flow in Pb+Pb collisions at √sNN = 5.02 TeV with the ATLAS detector.
Journal of High Energy Physics
, 2020
(1)
, Article 51. 10.1007/JHEP01(2020)051.
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Abstract
Multi-particle azimuthal cumulants are measured as a function of centrality and transverse momentum using 470 µb −1 of Pb+Pb collisions at √ sNN = 5.02 TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-byevent fluctuations of harmonic flow coefficients vn and correlated fluctuations between two harmonics vn and vm. For the first time, a non-zero four-particle cumulant is observed for dipolar flow, v1. The four-particle cumulants for elliptic flow, v2, and triangular flow, v3, exhibit a strong centrality dependence and change sign in ultra-central collisions. This sign change is consistent with significant non-Gaussian fluctuations in v2 and v3. The four-particle cumulant for quadrangular flow, v4, is found to change sign in mid-central collisions. Correlations between two harmonics are studied with three- and four-particle mixed-harmonic cumulants, which indicate an anti-correlation between v2 and v3, and a positive correlation between v2 and v4. These correlations decrease in strength towards central collisions and either approach zero or change sign in ultra-central collisions. To investigate the possible flow fluctuations arising from intrinsic centrality or volume fluctuations, the results are compared between two different event classes used for centrality definitions. In peripheral and mid-central collisions where the cumulant signals are large, only small differences are observed. In ultra-central collisions, the differences are much larger and transverse momentum dependent. These results provide new information to disentangle flow fluctuations from the initial and final states, as well as new insights on the influence of centrality fluctuations.
| Type: | Article |
|---|---|
| Title: | Fluctuations of anisotropic flow in Pb+Pb collisions at √sNN = 5.02 TeV with the ATLAS detector |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1007/JHEP01(2020)051 |
| Publisher version: | http://dx.doi.org/10.1007/JHEP01(2020)051 |
| Language: | English |
| Additional information: | This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited |
| Keywords: | Hadron-Hadron scattering (experiments), Heavy-ion collision, Collective flow, Event-by-event fluctuation, Particle correlations and fluctuations |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10090601 |
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