Infrared singularities of multi-leg QCD amplitudes with a massive parton at three loops

TL;DR

This paper derives the three-loop infrared singularity structure of QCD amplitudes involving a massive parton, providing new analytical expressions and a novel regularization method, crucial for top quark production predictions.

Contribution

It presents the first analytical expression for tripole correlations between one massive and two massless partons at three loops and introduces a new regularization approach for infrared divergences.

Findings

Derived three-loop anomalous dimensions for mixed massive and massless partons.

Obtained the first analytical expression for tripole correlations involving a massive parton.

Developed a novel regularization method for infrared divergences in momentum space.

Abstract

We derive the structure of three-loop anomalous dimensions governing infrared singularities of QCD amplitudes with one massive and an arbitrary number of massless external partons. The contributions of tripole and quadrupole correlations involving a massive parton are studied in details. The analytical expression of tripole correlations between one massive and two massless partons is obtained at three loops for the first time. We regularize the infrared divergences in the soft matrix element in a novel approach, where no extra scale dependence is involved, and the calculation can be performed in momentum space. Our results are essential to improve the theoretical predictions of single top and top quark pair productions at hadron colliders.