Measurement of isolated photon production in pp and PbPb collisions at √ s NN = 2.76 TeV with CMS

Abstract

Isolated photon production is measured in pp and PbPb collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |ζ| < 1.44 and transverse energies ET 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 ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities. © 2013 CERN.