The QCD form factor of heavy quarks at NNLO

TL;DR

This paper provides an analytical calculation of two-loop QCD corrections to the electromagnetic form factor of heavy quarks, extending previous results and enabling improved high-energy and small-mass predictions for heavy-quark processes.

Contribution

It presents the first complete two-loop calculation of the heavy-quark form factor including all epsilon terms and extends to three-loop expansions in the high-energy limit.

Findings

Calculated two-loop QCD corrections to heavy-quark form factor.

Derived improved three-loop high-energy expansions.

Discussed implications for massive n-parton amplitude predictions.

Abstract

We present an analytical calculation of the two-loop QCD corrections to the electromagnetic form factor of heavy quarks. The two-loop contributions to the form factor are reduced to linear combinations of master integrals, which are computed through higher orders in the parameter of dimensional regularization epsilon=(4-D)/2. Our result includes all terms of order epsilon at two loops and extends the previous literature. We apply the exponentiation of the heavy-quark form factor to derive new improved three-loop expansions in the high-energy limit. We also discuss the implications for predictions of massive n-parton amplitudes based on massless results in the limit, where the quark mass is small compared to all kinematical invariants.