Speaker
Peter Alan Steinberg
(Brookhaven National Laboratory (US))
Description
ATLAS has measured prompt photon production in sqrt(s_NN) = 2.76 TeV Pb+Pb collisions using data collected in
2011 with an integrated luminosity of 0.14 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. A multi-parameter selection on a set of nine shower properties,
coupled with an isolation criterion based on the energy deposited in the cone around a photon, gives measured
purities ranging from 50% at low pT to greater than 90% at high pT. Photon yields, scaled by the mean nuclear
thickness function, will be presented as a function of collision centrality, pseudorapidity (in two intervals |eta| < 1.37
and 1.52 < |eta|< 2.37) and transverse momentum (from 22 < pT < 280 GeV). The scaled yields will be compared to
expectations from JETPHOX (perturbative QCD calculations at next to leading order), as are the ratios of the
forward yields to those near mid-rapidity.
| On behalf of collaboration: | ATLAS |
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Primary author
Peter Alan Steinberg
(Brookhaven National Laboratory (US))
