Study of jet quenching with isolated-photon+jet correlations in PbPb and pp collisions at [formula omitted].

Abstract Measurements of azimuthal angle and transverse momentum (p T ) correlations of isolated photons and associated jets are reported for p p and PbPb collisions at s NN = 5.02 TeV. The data were recorded with the CMS detector at the CERN LHC. For events containing a leading isolated photon with p T γ > 40 GeV / c and an associated jet with p T jet > 30 GeV / c , the photon+jet azimuthal correlation and p T imbalance in PbPb collisions are studied as functions of collision centrality and p T γ. The results are compared to p p reference data collected at the same collision energy and to predictions from several theoretical models for parton energy loss. No evidence of broadening of the photon+jet azimuthal correlations is observed, while the ratio p T jet / p T γ decreases significantly for PbPb data relative to the p p reference. All models considered agree within uncertainties with the data. The number of associated jets per photon with p T γ > 80 GeV / c is observed to be shifted towards lower p T jet values in central PbPb collisions compared to p p collisions. [ABSTRACT FROM AUTHOR]