Numerical integration of the double- and triple-box integrals using threshold subtraction

TL;DR

This paper presents a numerical method for integrating complex two- and three-loop scalar integrals, advancing calculations needed for precise predictions in particle physics.

Contribution

It introduces the threshold subtraction technique for numerical integration of multi-loop integrals, enabling progress towards full NNLO virtual corrections in massive vector boson production.

Findings

Successfully applied threshold subtraction to two- and three-loop integrals

Paves the way for more accurate NNLO calculations in particle physics

First implementation of this method for such complex integrals

Abstract

We numerically integrate finite two- and three-loop scalar integrals using the threshold subtraction method. This represents a first step towards extending our calculation of the $N_f$-part to the full NNLO virtual corrections for the production of massive vector bosons.