Speaker
Description
We present analytic expressions for the one-loop QCD helicity amplitudes contributing to top-quark
pair production in association with a photon or a jet at the Large Hadron Collider (LHC), evaluated
through O(ϵ^2) in the dimensional regularisation parameter, ϵ.
These amplitudes are required to construct the two-loop hard functions that enter the NNLO QCD computation.
The helicity amplitudes are expressed as linear combinations of algebraically independent components of the ϵ-expanded
master integrals, with the corresponding rational coefficients written in terms of momentum-twistor variables.
We derive differential equations for the pentagon functions, which enable efficient numerical evaluation via generalised power series expansion method.
