Presampler scale studies using electrons from Z boson decays.

A precise calibration of energy measurement of photons and electrons plays a crucial role in various precision measurements carried out in ATLAS, such as the Higgs boson mass and couplings measurements in the di-photon channel or for a precise measurement of the W boson mass. One of the key inputs to the energy regression algorithm, is an estimate of the energy lost by electrons and photons when interacting with passive volumes of the detector before reaching the calorimeter (e.g. inner detector, cryostat walls, etc). This estimate is provided by the presampler, an active layer of liquid argon positioned in front of the electromagnetic calorimeters. The project is focusing on the in situ calibration of the presampler energy scale using electrons from Z boson decays recorded in LHC Run 2 data.