Forward-backward asymmetry in top quark-antiquark production

Abstract

We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a data set corresponding to an integrated luminosity of $5.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the $t\overline{t}$ forward-backward asymmetry to be $(9.2\ifmmode\pm\else\textpm\fi{}3.7)%$ at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be $(19.6\ifmmode\pm\else\textpm\fi{}6.5)%$. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be $(15.2\ifmmode\pm\else\textpm\fi{}4.0)%$. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.