Threshold expansion of the gg(qq) -> QQ+X cross section at O(alpha_s^4)

Abstract

We derive the complete set of velocity-enhanced terms in the expansion of the total cross section for heavy-quark pair production in hadronic collisions at next-to-next-to-leading order. Our expression takes into account the effects of soft-gluon emission as well as that of potential-gluon exchanges. We prove that there are no enhancements due to subleading soft-gluon couplings multiplying the leading Coulomb singularity.Comment: 11 pages, 2 figures, published erratum included at the end of the paper, updated attached Mathematica fil