Top quark production at threshold with O( αs2) accuracy

Abstract

We calculate the next-to-next-to-leading order correction to the cross section for top quark pair production in e + e − annihilation in the threshold region, resumming all O[( α s / β) n × ( α s 2, β 2, α s β)] terms of perturbation series. We find that the magnitude of the NNLO correction is comparable to the size of the NLO corrections.