Centrality dependence of the pseudorapidity density distribution for charged particles in Pb-Pb collisions at root s(NN)=5.02 TeV


Adam J., Adamova D., Aggarwal M. M., Rinella G. A., Agnello M., Agrawal N., ...More

PHYSICS LETTERS B, vol.772, pp.567-577, 2017 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 772
  • Publication Date: 2017
  • Doi Number: 10.1016/j.physletb.2017.07.017
  • Journal Name: PHYSICS LETTERS B
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.567-577
  • Bursa Uludag University Affiliated: No

Abstract

We present the charged-particle pseudorapidity density in Pb-Pb collisions at root s(NN) = 5.02 TeV in centrality classes measured by ALICE. The measurement covers a wide pseudorapidity range from -3.5 to 5, which is sufficient for reliable estimates of the total number of charged particles produced in the collisions. For the most central (0-5%) collisions we find 21 400 +/- 1 300, while for the most peripheral (80-90%) we find 230 +/- 38. This corresponds to an increase of (27 +/- 4)% over the results at root s(NN) = 2.76 TeV previously reported by ALICE. The energy dependence of the total number of charged particles produced in heavy-ion collisions is found to obey a modified power-law like behaviour. The charged-particle pseudorapidity density of the most central collisions is compared to model calculations-none of which fully describes the measured distribution. We also present an estimate of the rapidity density of charged particles. The width of that distribution is found to exhibit a remarkable proportionality to the beam rapidity, independent of the collision energy from the top SPS to LHC energies. (C) 2017 The Author(s). Published by Elsevier B.V.