Progress on two-loop non-propagator integrals

TL;DR

This paper reviews recent advancements in calculating two-loop multi-leg integrals, especially four-point functions, addressing computational challenges that have limited progress in exclusive observable computations beyond one loop.

Contribution

It highlights recent progress in evaluating two-loop four-point functions, overcoming previous computational difficulties in multi-leg amplitude calculations.

Findings

Improved methods for two-loop four-point integral evaluation.

Enhanced understanding of multi-leg amplitude complexities.

Progress enabling more precise exclusive observable predictions.

Abstract

At variance with fully inclusive quantities, which have been computed already at the two- or three-loop level, most exclusive observables are still known only at one loop, as further progress was hampered up to very recently by the greater computational problems encountered in the study of multi-leg amplitudes beyond one loop. We discuss the progress made lately in the evaluation of two-loop multi-leg integrals, with particular emphasis on two-loop four-point functions.