Study of jet quenching using [gamma]-jet events in heavy ion collisions at 2.76TeV

Abstract

The kinematic correlations of isolated-[gamma]+jet scatterings in proton-proton and lead-lead collisions at centre-of-mass energy of 2.76TeV per nucleon pair are studied for the investigation of the jet quenching phenomena in hot and dense QCD medium. The analysis uses collision data delivered by the LHC and recorded by CMS detector at CERN. The angular correlation, the transverse momentum ratio and the rate of mono-photon events are measured and their dependence on the collisional impact parameter is examined in lead-lead collision. The results of proton-proton collisions are used as the reference to which the lead-lead results are compared. Significant energy loss of jets induced by the hot and dense medium, and its gradual rise in correlation to the size of the medium are observed in lead-lead collisions, while a modification of the direction of jet axis is not detected.