Massive planar and non-planar double box integrals for light Nf contributions to gg->tt

TL;DR

This paper computes master integrals for two-loop light fermionic corrections to top quark pair production via gluon fusion, using differential equations and polylogarithms, including complex non-planar topologies.

Contribution

It provides explicit calculations of master integrals for complex two-loop diagrams, including non-planar topologies with internal masses, advancing precision in theoretical predictions.

Findings

Computed master integrals in terms of multiple polylogarithms.

Simplified results using coproduct-augmented symbol calculus.

Addressed complex non-planar double box integrals with internal mass.

Abstract

We present the master integrals needed for the light fermionic two-loop corrections to top quark pair production in the gluon fusion channel. Via the method of differential equations we compute the results in terms of multiple polylogarithms in a Laurent series about d=4, where d is the space-time dimension. The most involved topology is a non-planar double box with one internal mass. We employ the coproduct-augmented symbol calculus and show that significant simplifications are possible for selected results using an optimised set of multiple polylogarithms.