Measurement of isolated photon production in pp and PbPb collisions at root s(NN)=2.76 TeV


Chatrchyan S., Khachatryan V., Sirunyan A. M., Tumasyan A., Adam W., Bergauer T., ...More

PHYSICS LETTERS B, vol.710, no.2, pp.256-277, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 710 Issue: 2
  • Publication Date: 2012
  • Doi Number: 10.1016/j.physletb.2012.02.077
  • Journal Name: PHYSICS LETTERS B
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.256-277
  • Keywords: CMS, Physics, Heavy-ions, Photons
  • Middle East Technical University Affiliated: Yes

Abstract

Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range vertical bar eta vertical bar < 1.44 and transverse energies E-T between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon E-T-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities. (C) 2012 CERN. Published by Elsevier BM. All rights reserved.