A measurement of the top-antitop (tt¯) charge asymmetry is presented using data corresponding to an integrated luminosity of 4.6 fb−1 of LHC pp collisions at a centreof-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: A C ℓℓ based on the identified charged leptons, and Att¯C, based on the reconstructed tt final state.
Comparison of measured values of charge asymmetry AC ll and ACtt steoretical forecasts SM. Ellipses correspond to 1σ and 2σ error contours.