Abstract:
This paper presents the electron and photon energy
calibration obtained with the ATLAS detector using 140 fb-1 of
LHC proton-proton collision data recorded at √(s) = 13 TeV
between 2015 and 2018. Methods for the measurement of electron and
photon energies are outlined, along with the current knowledge of
the passive material in front of the ATLAS electromagnetic
calorimeter. The energy calibration steps are discussed in detail,
with emphasis on the improvements introduced in this paper. The
absolute energy scale is set using a large sample of Z-boson
decays into electron-positron pairs, and its residual dependence on
the electron energy is used for the first time to further constrain
systematic uncertainties. The achieved calibration uncertainties are
typically 0.05% for electrons from resonant Z-boson decays, 0.4%
at E
T ∼ 10 GeV, and 0.3% at E
T ∼ 1 TeV; for photons at E
T ∼ 60 GeV, they are 0.2% on average. This is more
than twice as precise as the previous calibration. The new energy
calibration is validated using J/ψ → ee and radiative
Z-boson decays.