We present a measurement of the charge asymmetry in top-antitop production
using data corresponding to an integrated luminosity of 0.70fb−1 of
proton-proton collisions at s​=7 TeV collected by the ATLAS detector.
The top pair events decaying semileptonically (lepton+jets channel) to either
an electron or muon, missing transverse energy and at least four jets are
selected. The reconstruction of the ttˉ events was performed using a
kinematic likelihood approach. The difference of absolute values of top and
antitop rapidities is used to define the charge asymmetry: AC​=(N(∣ΔY∣>0)−N(∣ΔY∣0)+N(∣ΔY∣<0)). To allow
comparisons with theory calculations, a Bayesian unfolding technique is applied
to correct the measured ∣ΔY∣ distributions for acceptance and detector
effects. The top charge asymmetry in both channels (e and mu) after correction
is measured to be: AC​=−0.009±0.023(stat)±0.032(syst) (e+jets
channel) and AC​=−0.028±0.019(stat)±0.022(syst) (μ+jets
channel) giving a combined result of : AC​=−0.024±0.016(stat)±0.023(syst). These results are compatible with the Standard Model predictions
of AC​=0.006.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 3 pages, 4 figure