Light-quark two-loop corrections to heavy-quark pair production in the gluon fusion channel

Understand

We calculate the two-loop corrections to heavy-quark pair production in the gluon fusion channel which arise from diagrams involving a closed light-quark loop.

• The calculation is carried out by keeping the exact dependence on the heavy-quark mass.
• The analytic results are written in terms of logarithms, classical polylogarithms Li_n (n=2,3,4), and genuine multiple polylogarithms Li_{2,2}.
• The functional arguments are rational expressions of two independent external invariants and they are chosen in such a way that the functions are real in all the physical phase-space points.