Centrality, rapidity and pT dependence of isolated prompt photon production in lead-lead collisions at sqrt(sNN)= 2.76 TeV with the ATLAS detector at the LHC

20 May 2014, 12:50
titanium (darmstadtium)



Schlossgraben 1 64283 Darmstadt Germany
Contributed Talk Jets Jets


Peter Alan Steinberg (Brookhaven National Laboratory (US))


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

Primary author

Peter Alan Steinberg (Brookhaven National Laboratory (US))

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