We consider the Lagrange density of non-relativistic Quantum Chromodynamics expanded up to order 1/m2, where m is the heavy quark mass, and compute several matching coefficients up to two-loop order. Our results are building blocks for next-to-next-to-next-to-leading logarithmic and next-to-next-to-next-to-next-to-leading order corrections to the threshold production of top quark pairs and the decay of heavy quarkonia. We describe the techniques used for the calculation and provide analytic results for a general covariant gauge.
@article{arxiv.1907.08227,
title = {Matching coefficients in NRQCD to two-loop accuracy},
author = {Marvin Gerlach and Go Mishima and Matthias Steinhauser},
journal= {arXiv preprint arXiv:1907.08227},
year = {2019}
}