Measurement of the Charge Asymmetry in Top-Quark Pair Production in the Lepton-Plus-Jets Final State in pp Collision Data at √s̅ = 8 TeV with the ATLAS Detector


This paper reports inclusive and differential measurements of the tt̅ charge asymmetry A_C in 20.3 fb⁻¹ of √s̅ = 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 tt̅ system. The tt̅ 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 tt̅ event kinematics. A Bayesian unfolding procedure is performed to infer the asymmetry at parton level from the observed data distribution. The inclusive tt̅ charge asymmetry is measured to be A_C = 0.009 ± 0.005 (stat. + syst.). The inclusive and differential measurements are compatible with the values predicted by the Standard Model.


Includes erratum.


Quarks, Charge-parity asymmetry, Leptons (Nuclear physics), Jets (Nuclear physics), Proton-proton interactions


CC BY 4.0 (Attribution), ©2016 CERN, for the ATLAS Collaboration