Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV/c in PbPb collisions at √sNN = 5.02TeV

Authors

S. Chatrchyan
Ekaterina Avdeeva, University of Nebraska-LincolnFollow
Kenneth Bloom, University of Nebraska-LincolnFollow
S. Bose, University of Nebraska - LincolnFollow
Jamila Butt, University of Nebraska - Lincoln
Daniel R. Claes, University of Nebraska-LincolnFollow
Aaron Dominguez, University of Nebraska-LincolnFollow
M. Eads, University of Nebraska-Lincoln, Lincoln,Follow
R. Gonzalez Suarez, University of Nebraska - Lincoln
P. Jindal, University of Nebraska - Lincoln
J. Keller, University of Nebraska - LincolnFollow
D. Knowlton, University of Nebraska-LincolnFollow
Ilya Kravchenko, University of Nebraska-LincolnFollow
Jose Lazo-Flores, University of Nebraska-LincolnFollow
Helena Malbouisson, University of Nebraska - Lincoln
Sudhir Malik, University of Nebraska - LincolnFollow
F. Meier, University of Nebraska-Lincoln, Lincoln,Follow
Gregory Snow, University of Nebraska - LincolnFollow

Date of this Version

2018

Citation

Physics Letters B 776 (2018) 195–216

Comments

© 2017 The Author.

Open access

https://doi.org/10.1016/j.physletb.2017.11.041

Abstract

The Fourier coefficients v₂ and v₃ characterizing the anisotropy of the azimuthal distribution of charged particles produced in PbPb collisions at √^sNN = 5.02TeV are measured with data collected by the CMS experiment. The measurements cover a broad transverse momentum range, 1 < pT < 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 v₂ 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 ∼ 60–80 GeV/c, in all examined centrality classes. The v₃ coefficient, only measured with the scalar product method, tends to zero for p_T [?] 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.