Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run-1 data

H. WAHLBERG Y ATLAS COLLABORATION

EUROPEAN PHYSICAL JOURNAL C - PARTICLES AND FIELDS

SPRINGER

Lugar: Berlin; Año: 2016

1434-6044

The algorithms used by the ATLAS Collaboration to reconstruct and identify prompt photonsare described. Measurements of the photon identification efficiencies are reported, using√√4.9 fb −1 of pp collision data collected at the LHC at s = 7 TeV and 20.3 fb −1 at s = 8 TeV.The efficiencies are measured separately for converted and unconverted photons, in four dif-ferent pseudorapidity regions, for transverse momenta between 10 GeV and 1.5 TeV. Theresults from the combination of three data-driven techniques are compared to the predic-tions from a simulation of the detector response, after correcting the electromagnetic showermomenta in the simulation for the average differences observed with respect to data. Data-to-simulation efficiency ratios used as correction factors in physics measurements are determ-ined to account for the small residual efficiency differences. These factors are measured withuncertainties between 0.5% and 10% in 7 TeV data and between 0.5% and 5.6% in 8 TeVdata, depending on the photon transverse momentum and pseudorapidity.