Measurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment
2023
Abstract
A measurement of the charge asymmetry in top-quark pair (t-t) production in association with a photon is presented. The measurement is performed in the single-lepton t-tdecay channel using proton-protoncollision data collected with the ATLAS detector at the Large Hadron Collider at CERN at a centre-of-mass-energy of 13TeV during the years 2015-2018, corresponding to an integrated luminosity of 139fb-1.
The charge asymmetry is obtained from the distribution of the difference of the absolute rapidities of the top quark and antiquark using a profile likelihood unfolding approach. It is measured to be AC=-0.003 +-0.029in agreement with the Standard Model expectation.