We evaluate the planar two-loop QCD diagrams contributing to the leading color coefficient of the heavy-quark pair production cross section, in the quark-antiquark annihilation channel. We obtain the leading color coefficient in an analytic form, in terms of one- and two-dimensional harmonic polylogarithms of maximal weight 4. The result is valid for arbitrary values of the Mandelstam invariants s and t, and of the heavy-quark mass m. Our findings agree with previous analytic results in the small-mass limit and numerical results for the exact amplitude.
@article{arxiv.0906.3671,
title = {Two-Loop Planar Corrections to Heavy-Quark Pair Production in the Quark-Antiquark Channel},
author = {R. Bonciani and A. Ferroglia and T. Gehrmann and C. Studerus},
journal= {arXiv preprint arXiv:0906.3671},
year = {2009}
}