Electron efficiency measurements with the ATLAS detector using 2012 LHC proton-proton collision data

Abstract

This paper describes the algorithms for the reconstruction and identification of electronsin the central region of the ATLAS detector at the Large Hadron Collider (LHC). Thesealgorithms were used for all ATLAS results with electrons in the final state that are based√on the 2012 pp collision data produced by the LHC at s = 8 TeV. The efficiency of thesealgorithms, together with the charge misidentification rate, is measured in data and evaluatedin simulated samples using electrons from Z → ee, Z → eeγ and J/ψ → ee decays. Forthese efficiency measurements, the full recorded data set, corresponding to an integratedluminosity of 20.3 fb −1 , is used. Based on a new reconstruction algorithm used in 2012,the electron reconstruction efficiency is 97% for electrons with E T = 15 GeV and 99% atE T = 50 GeV. Combining this with the efficiency of additional selection criteria to rejectelectrons from background processes or misidentified hadrons, the efficiency to reconstructand identify electrons at the ATLAS experiment varies from 65% to 95%, depending on thetransverse momentum of the electron and background rejection.