On the Soft-Gluon Resummation in Top Quark Pair Production at Hadron Colliders

TL;DR

This paper identifies a previously overlooked contribution in the threshold resummation for top quark pair production, significantly affecting theoretical cross section estimates at hadron colliders.

Contribution

It derives an exact analytic expression for a new contribution to the NLO/NLL resummed cross section, improving the accuracy of theoretical predictions.

Findings

Large numerical impact on the resummed cross section

Potential decrease of a few percent in cross section estimates at the LHC

Highlights importance of including the new contribution for precise predictions

Abstract

We uncover a contribution to the NLO/NLL threshold resummed total cross section for top quark pair production at hadron colliders, which has not been taken into account in earlier literature. We derive this contribution - the difference between the singlet and octet hard (matching) coefficients - in exact analytic form. The numerical impact of our findings on the Sudakov resummed cross section turns out to be large, and comparable in size to the current estimates for the theoretical uncertainty of the total cross section. A rough estimate points toward a few percent decrease of the latter at the LHC.