Measurement of the forward-backward asymmetry in the distribution of leptons in t(t)over-bar events in the lepton plus jets channel
Abstract
We present measurements of the forward-backward asymmetry in the angular distribution of leptons from decays of top quarks and antiquarks produced in proton-antiproton collisions. We consider the final state containing a lepton and at least three jets.
The entire sample of data collected by the D0 experiment during Run II of the Fermilab Tevatron Collider, corresponding to 9.7 fb(-1) of integrated luminosity, is used. The asymmetry measured for reconstructed leptons is A(FB)(l) = (2.9 +/- 2.1(stat.)(-1.7)(+1.5) (syst.))%.
When corrected for efficiency and resolution effects within the lepton rapidity coverage of vertical bar y(l)vertical bar < 1.5, the asymmetry is found to be A(FB)(l) = (4.2 +/- 2.3(stat.)(-2.0)(+1.7) (syst.))%. We examine the dependence of A(FB)(l) on the transverse momentum and rapidity of the lepton.
Combination with the asymmetry measured in the final states containing two leptons yields A(FB)(l) = (4.2 +/- 2.0(stat.) +/- 1.4(syst.))%. The results are in agreement with predictions from the next-to-leading-order QCD generator MC@NLO, which predicts an asymmetry of A(FB)(l) = 2.0% for vertical bar y(l)vertical bar < 1.5.