Azimuthal anisotropy of charged particles with transverse momentum up to 100GeV/c in PbPb collisions at root S-NN=5.02 TeV


Sirunyan A. M. , Tumasyan A., Adam W., Asilar E., Bergauer T., Brandstetter J., ...More

PHYSICS LETTERS B, vol.776, pp.195-216, 2018 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Volume: 776
  • Publication Date: 2018
  • Doi Number: 10.1016/j.physletb.2017.11.041
  • Title of Journal : PHYSICS LETTERS B
  • Page Numbers: pp.195-216
  • Keywords: CMS, QGP, High-pT, Flow, Parton energy loss, Jet quenching, PLUS AU COLLISIONS, HIGH-P(T) HADRON SUPPRESSION, QUARK-GLUON PLASMA, AU+AU COLLISIONS, ROOT-S(NN)=130 GEV, ELLIPTIC FLOW, DEPENDENCE, DISTRIBUTIONS, PERSPECTIVE, SPECTRA

Abstract

The Fourier coefficients v(2) and v(3) characterizing the anisotropy of the azimuthal distribution of charged particles produced in PbPb collisions at root S-NN = 5.02 TeV are measured with data collected by the CMS experiment. The measurements cover a broad transverse momentum range, 1 < p(T) < 100 GeV/c. The analysis focuses on the p(T) > 10 GeV/c range, where anisotropic azimuthal distributions should reflect the path-length dependence of parton energy loss in the created medium. Results are presented in several bins of PbPb collision centrality, spanning the 60% most central events. The v(2) coefficient is measured with the scalar product and the multiparticle cumulant methods, which have different sensitivities to initial-state fluctuations. The values from both methods remain positive up to p(T) similar to 60-80 GeV/c, in all examined centrality classes. The v(3) coefficient, only measured with the scalar product method, tends to zero for p(T) greater than or similar to 20 GeV/c. Comparisons between theoretical calculations and data provide new constraints on the path-length dependence of parton energy loss in heavy ion collisions and highlight the importance of the initial-state fluctuations. (C) 2017 The Author. Published by Elsevier B.V.