The identification of prompt photons and the rejection of background, originating mostly from photons from hadron decays, relies on the high granularity of the ATLAS calorimeter. The electron identification is based on a likelihood discriminant to separate isolated electron from background electron originating from photon conversions, hadron misidentification and heavy flavour decays. Additionally, isolation variables provide further handles to separate signal and background. The measurements of the efficiencies of the electron and photon identification and isolation selections are performed with data. Tag and probe techniques are used with Z→ee, J/ψ →ee and Z→l lγ decays. Inclusive photon samples are also used to measure photon identification efficiency.
The results of these measurement with the pp collisions data recorded in 2015 at √s = 13 TeV, corresponding to an integrated luminosity of 3.2 fb−1 are presented, as well as a first look at 2016 data.