Centrality, rapidity and pTpT dependence of isolated prompt photon production in lead–lead collisions at sNN=2.76 TeV with the ATLAS detector at the LHC

The ATLAS experiment at the LHC has measured prompt photon production in sNN=2.76 TeV Pb + Pb collisions using data collected in 2011 with an integrated luminosity of 0.14 nb−10.14 nb−1. The measurement is performed with a hermetic, longitudinally segmented calorimeter, which gives excellent spatial and energy resolution, and detailed information about the shower shape of each measured photon. Using a selection based on shower shapes and an isolation criterion gives measured purities between approximately 50–90%, depending on pTpT, η   and centrality. Photon yields, scaled by the mean nuclear thickness function, are determined as a function of collision centrality, pseudorapidity (in two intervals |η|<1.37|η|<1.37 and 1.52<|η|<2.371.52<|η|<2.37) and transverse momentum (22