Performance of high-pT electron identification in lead-lead collisions at 5.02 TeV with the ATLAS detector

Electrons may be copiously produced in heavy-ion collisions. They constitute important final states from leptonic decay channels of Z and W bosons. Their reconstruction and identification is very challenging in heavy-ion collisions due to large detector occupancy varying strongly with the collision centrality. The presented material will discuss performance of high-pT electrons, including trigger, reconstruction and identification in lead-lead data collected at 5.02 TeV by the ATLAS detector in 2015. Studies will be focused on optimization of the likelihood approach for identifying signal electrons coming mostly from W and Z boson decays. The likelihood method has been applied successfully in proton-proton collisions in the ATLAS experiment, but in order to perform well in lead-lead collisions, centrality dependence has had to be considered. Also during the 2015 heavy-ion run the ATLAS tracker operated with a different gas mixture from the nominal one used for electron identification in proton-proton collisions. Its impact on electron performance also will be discussed.