Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run 2 data collected in 2015 and 2016

Miucci, Antonio; Merlassino, Claudia; Haug, Sigve; Weber, Michael; Anders, John Kenneth; Beck, Hans Peter; Ereditato, Antonio; Rimoldi, Marco; Weston, Thomas Daniel (2019). Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run 2 data collected in 2015 and 2016. The European physical journal. C, Particles and fields, 79(3) Springer 10.1140/epjc/s10052-019-6650-6

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The efficiency of the photon identification criteria in the ATLAS detector is measured using 36.1 fb1 to 36.7 fb1 of pp collision data at s√=13 TeV collected in 2015 and 2016. The efficiencies are measured separately for converted and unconverted isolated photons, in four different pseudorapidity regions, for transverse momenta between 10 GeV and 1.5 TeV. The results from the combination of three data-driven techniques are compared with the predictions from simulation after correcting the variables describing the shape of electromagnetic showers in simulation for the average differences observed relative to data. Data-to-simulation efficiency ratios are determined to account for the small residual efficiency differences. These factors are measured with uncertainties between 0.5% and 5% depending on the photon transverse momentum and pseudorapidity. The impact of the isolation criteria on the photon identification efficiency, and that of additional soft pp interactions, are also discussed. The probability of reconstructing an electron as a photon candidate is measured in data, and compared with the predictions from simulation. The efficiency of the reconstruction of photon conversions is measured using a sample of photon candidates from Z→μμγ events, exploiting the properties of the ratio of the energies deposited in the first and second longitudinal layers of the ATLAS electromagnetic calorimeter.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Miucci, Antonio, Merlassino, Claudia, Haug, Sigve, Weber, Michele, Anders, John Kenneth, Beck, Hans Peter, Ereditato, Antonio, Rimoldi, Marco, Weston, Thomas Daniel


500 Science > 530 Physics









Date Deposited:

15 Jun 2020 10:53

Last Modified:

05 Dec 2022 15:38

Publisher DOI:


Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwaehnt; ATLAS collaboration




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