Speaker
Description
In this talk, I will present the calculation of the Feynman integrals entering the two-loop scattering amplitudes for top–antitop pair production in association with a photon, in the leading-colour approximation, required for NNLO QCD predictions at hadron colliders.
The kinematics of the process, involving six independent invariants and up to three massive propagators, leads to a high degree of algebraic and analytic complexity, with several sectors featuring nested square roots and elliptic integrals.
Using finite-field techniques, we reconstruct the differential equations satisfied by a suitable basis of master integrals that we identify. We define a set of special functions in terms of which all master integrals can be expressed, and solve their differential equations numerically.