Measurement of the distributions of event-by-event flow harmonics in lead-lead collisions at √SNN = 2.76 TeV with the ATLAS detector at the LHC

G. Aad, T. Abajyan, B. Abbott, J. Abdallah, S. Abdel Khalek, A. A. Abdelalim, O. Abdinov, R. Aben, B. Abi, M. Abolins, O. S. AbouZeid, H. Abramowicz, H. Abreu, Y. Abulaiti, B. S. Acharya, L. Adamczyk, D. L. Adams, T. N. Addy, J. Adelman, S. AdomeitT. Adye, S. Aefsky, J. A. Aguilar-Saavedra, M. Agustoni, S. P. Ahlen, F. Ahles, A. Ahmad, M. Ahsan, G. Aielli, T. P.A. Åkesson, G. Akimoto, A. V. Akimov, M. A. Alam, J. Albert, S. Albrand, M. J. Alconada Verzini, M. Aleksa, I. N. Aleksandrov, F. Alessandria, C. Alexa, G. Alexander, G. Alexandre, T. Alexopoulos, M. Alhroob, M. Aliev, G. Alimonti, J. Alison, B. M.M. Allbrooke, L. J. Allison, P. P. Allport

Research output: Contribution to journalArticlepeer-review

112 Scopus citations

Abstract

The distributions of event-by-event harmonic flow coefficients υn for n = 2-4 are measured in √sNN = 2.76TeV Pb+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using charged particles with transverse momentum pT > 0.5GeV and in the pseudorapidity range |η| < 2.5 in a dataset of approximately 7 μb-1 recorded in 2010. The shapes of the υn distributions suggest that the associated flow vectors are described by a two-dimensional Gaussian function in central collisions for υ2 and over most of the measured centrality range for υ3 and υ4. Significant deviations from this function are observed for υ2 in mid-central and peripheral collisions, and a small deviation is observed for υ3 in mid-central collisions. In order to be sensitive to these deviations, it is shown that the commonly used multi-particle cumulants, involving four particles or more, need to be measured with a precision better than a few percent. The υn distributions are also measured independently for charged particles with 0.5 < pT < 1 GeV and pT > 1 GeV. When these distributions are rescaled to the same mean values, the adjusted shapes are found to be nearly the same for these two pT ranges. The υn distributions are compared with the eccentricity distributions from two models for the initial collision geometry: a Glauber model and a model that includes corrections to the initial geometry due to gluon saturation effects. Both models fail to describe the experimental data consistently over most of the measured centrality range. Copyright CERN.

Original languageEnglish (US)
JournalJournal of High Energy Physics
Volume2013
Issue number11
DOIs
StatePublished - Nov 2013

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

Keywords

  • Event-by-event fluctuation
  • Hadron-Hadron scattering
  • Harmonic flow
  • Heavy-ion collision
  • Unfolding

Fingerprint Dive into the research topics of 'Measurement of the distributions of event-by-event flow harmonics in lead-lead collisions at √S<sub>NN</sub> = 2.76 TeV with the ATLAS detector at the LHC'. Together they form a unique fingerprint.

Cite this