The European Physical Journal C > 2016 > 76 > 12 > 1-42
Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run-1 data
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Abstract
The algorithms used by the ATLAS Collaboration to reconstruct and identify prompt photons are described. Measurements of the photon identification efficiencies are reported, using 4.9 fb $$^{-1}$$ - 1 of pp collision data collected at the LHC at $$\sqrt{s} = 7$$ s = 7 $$\text {TeV}$$ TeV and 20.3 fb $$^{-1}$$ - 1 at $$\sqrt{s} = 8$$ s = 8 $$\text {TeV}$$ TeV . The efficiencies are measured separately for converted and unconverted photons, in four different pseudorapidity regions, for transverse momenta between 10 $$\text {GeV}$$ GeV and 1.5 $$\text {TeV}$$ TeV . The results from the combination of three data-driven techniques are compared to the predictions from a simulation of the detector response, after correcting the electromagnetic shower momenta 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 determined to account for the small residual efficiency differences. These factors are measured with uncertainties between 0.5% and 10% in 7 $$\text {TeV}$$ TeV data and between 0.5% and 5.6% in 8 $$\text {TeV}$$ TeV data, depending on the photon transverse momentum and pseudorapidity.
Identifiers
journal ISSN : | 1434-6044 |
journal e-ISSN : | 1434-6052 |
DOI | 10.1140/epjc/s10052-016-4507-9 |