Towards numerical two-loop integrand reduction

Abstract

We present a method for the integrand-level reduction of two-loop helicity amplitudes in both $d=4-2ϵ$ and $d=4$ dimensions. The amplitude is expressed in terms of a set of Feynman integrals and their coefficients that depend on the external kinematics. The analysis presented in this paper, in conjunction with the ongoing development of the computational framework $\text{HELAC-2LOOP}$, paves the road for the construction of an automated program for two-loop amplitude calculations for arbitrary scattering processes.

Comments: 38 pages, 15 tables, 8 figures, accepted for publication in JHEP