Top-pair forward-backward asymmetry beyond next-to-leading order

Ahrens, V; Ferroglia, A; Neubert, M; Pecjak, B; Yang, L (2011). Top-pair forward-backward asymmetry beyond next-to-leading order. Physical Review D, 84(7):074004.

Abstract

We make use of recent results in effective theory and higher-order perturbative calculations to im- prove the theoretical predictions of the QCD contribution to the top-quark pair production forward- backward asymmetry at the Tevatron. In particular, we supplement the fixed-order NLO calculation with higher-order corrections from soft gluon resummation at NNLL accuracy performed in two dif- ferent kinematic schemes, which allows us to make improved predictions for the asymmetry in the pp ̄ and tt ̄ rest frames as a function of the rapidity and invariant mass of the tt ̄ pair. Furthermore, we provide binned results which can be compared with the recent measurements of the forward- backward asymmetry in events with a large pair invariant mass or rapidity difference. Finally, we calculate at NLO+NNLL order the top-quark charge asymmetry at the LHC as a function of a lower rapidity cut-off for the top and antitop quarks.

Abstract

We make use of recent results in effective theory and higher-order perturbative calculations to im- prove the theoretical predictions of the QCD contribution to the top-quark pair production forward- backward asymmetry at the Tevatron. In particular, we supplement the fixed-order NLO calculation with higher-order corrections from soft gluon resummation at NNLL accuracy performed in two dif- ferent kinematic schemes, which allows us to make improved predictions for the asymmetry in the pp ̄ and tt ̄ rest frames as a function of the rapidity and invariant mass of the tt ̄ pair. Furthermore, we provide binned results which can be compared with the recent measurements of the forward- backward asymmetry in events with a large pair invariant mass or rapidity difference. Finally, we calculate at NLO+NNLL order the top-quark charge asymmetry at the LHC as a function of a lower rapidity cut-off for the top and antitop quarks.

Statistics

Citations

81 citations in Web of Science®
85 citations in Scopus®