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


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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 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 710 Issue: 2
  • Publication Date: 2012
  • Doi Number: 10.1016/j.physletb.2012.02.077
  • Title of Journal : PHYSICS LETTERS B
  • Page Numbers: pp.256-277

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.