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Oxana Smirnova

Oxana Smirnova

Senior lecturer

Oxana Smirnova

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

Author

  • M Aaboud
  • Torsten Åkesson
  • Simona Bocchetta
  • Eric Corrigan
  • Caterina Doglioni
  • Kristian Gregersen
  • Eva Brottmann Hansen
  • Vincent Hedberg
  • Göran Jarlskog
  • Charles Kalderon
  • Edgar Kellermann
  • Balazs Konya
  • Else Lytken
  • Katja Mankinen
  • Ulf Mjörnmark
  • Geoffrey Mullier
  • Ruth Pöttgen
  • Trine Poulsen
  • Oxana Smirnova
  • L. Zwalinski

Summary, in English

The efficiency of the photon identification criteria in the ATLAS detector is measured using 36.1fb1 to 36.7fb1 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. © 2019, CERN for the benefit of the ATLAS collaboration.

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2019-03-07

Language

English

Publication/Series

European Physical Journal C

Volume

79

Issue

3

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1434-6044