Measurement of the charge asymmetry in dileptonic decays of top quark pairs in pp collisions at √s = 7 TeV using the ATLAS detector

Abstract

A measurement of the top-antitop (t¯t) charge asymmetry is presented using data corresponding to an integrated luminosity of 4.6 fb−1 of LHC pp collisions at a centre-of- mass energy of 7 TeV collected by the ATLAS detector. Events with two charged leptons, at least two jets and large missing transverse momentum are selected. Two observables are studied: Aℓℓ C based on the identified charged leptons, and At¯t C , based on the reconstructed t¯t final state. The asymmetries are measured to be Aℓℓ C = 0.024 ± 0.015 (stat.) ± 0.009 (syst.) , At¯t C = 0.021 ± 0.025 (stat.) ± 0.017 (syst.) . The measured values are in agreement with the Standard Model predictions.