Measurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment

A measurement of the charge asymmetry in top-quark pair (tt¯) production association with a photon is presented. The performed single-lepton tt¯ decay channel using proton–proton collision data collected ATLAS detector at Large Hadron Collider CERN centre-of-mass-energy 13 TeV during years 2015–2018, corresponding to an integrated luminosity 139 fb−1. obtained from distribution difference absolute rapidities top quark and antiquark profile likelihood unfolding approach. It measured be AC=−0.003±0.029 agreement Standard Model expectation.