Regularization-scheme dependence of QCD amplitudes in the massive case

TL;DR

This paper explores how different regularization schemes affect the calculation of QCD amplitudes with massive quarks at NNLO, providing a comprehensive understanding of scheme dependence in these computations.

Contribution

It determines the scheme dependence of heavy quark and cusp anomalous dimensions at NNLO using soft-collinear effective theory, completing the description of scheme dependence in QCD amplitudes.

Findings

Scheme dependence of heavy quark anomalous dimensions quantified.

Relation between FDH and dimensional reduction schemes established.

Results validated against explicit NNLO form factor computations.

Abstract

We investigate QCD amplitudes with massive quarks computed in the four-dimensional helicity scheme (FDH) and dimensional reduction at NNLO and describe how they are related to the corresponding amplitudes computed in conventional dimensional regularization. To this end, the scheme dependence of the heavy quark and the velocity-dependent cusp anomalous dimensions is determined using soft-collinear effective theory. The results are checked against explicit computations of massive form factors in FDH at NNLO. Our results complete the description of the scheme dependence of QCD amplitudes at NNLO.