Measurement of the charge asymmetry in top quark pair production in pp collisions at root s=7 TeV using the ATLAS detector

Abstract

A measurement of the top-antitop production charge asymmetry A(C) is presented using data corresponding to an integrated luminosity of 1.04 fb(-1) of pp collisions at root s = 7 TeV collected by the ATLAS detector at the LHC. Events are selected with a single lepton (electron or muon), missing transverse momentum and at least four jets of which at least one jet is identified as coming from a b-quark. A kinematic fit is used to reconstruct the t (t) over bar event topology. After background subtraction, a Bayesian unfolding procedure is performed to correct for acceptance and detector effects. The measured value of A(C) is A(C) =-0.019+/-0.028 (stat.)+/-0.024 (syst.), consistent with the prediction from the MC"NLO Monte Carlo generator of A(C) = 0.006+/-0.002. Measurements of AC in two ranges of invariant mass of the top-antitop pair are also shown.