Loop integral evaluation and asymptotic expansion with pySecDec

Abstract

pySecDec is a computer program that evaluates arbitrary multi-loop Feynman integrals numerically as expansions in the dimensional regulator based on the sector decomposition approach. In the recent release version 1.5 pySecDec introduces asymptotic expansion in the kinematic ratios using the method of expansion by regions, and an automatic adaptive evaluation of weighted sums of integrals (e.g. amplitudes). In this article we discuss how these features work, and what performance benefits they bring.