Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at √s = 8 TeV with the ATLAS detector

Abstract

This paper reports inclusive and differential measurements of the tt̄ charge asymmetry ACin 20.3 fb−1of √s = 8 TeV pp collisions recorded by the ATLAS experiment at the Large Hadron Collider at CERN. Three differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the tt̄ system. The tt̄ pairs are selected in the single-lepton channels (e or μ) with at least four jets, and a likelihood fit is used to reconstruct the tt̄ event kinematics. A Bayesian unfolding procedure is performed to infer the asymmetry at parton level from the observed data distribution. The inclusive tt̄ charge asymmetry is measured to be AC= 0.009 ± 0.005 (stat. + syst.). The inclusive and differential measurements are compatible with the values predicted by the Standard Model.