Contributor info: Prof. Stefan Weinzierl

Hjalte Frellesvig, Stefan Weinzierl

SciPost Phys. 16, 150 (2024) · published 6 June 2024 | Toggle abstract · pdf

We investigate $\varepsilon$-factorised differential equations, uniform transcendental weight and purity for Feynman integrals. We are in particular interested in Feynman integrals beyond the ones which evaluate to multiple polylogarithms. We show that a $\varepsilon$-factorised differential equation does not necessarily lead to Feynman integrals of uniform transcendental weight. We also point out that a proposed definition of purity works locally, but not globally.

Philipp Alexander Kreer, Robert Runkel, Stefan Weinzierl

SciPost Phys. Proc. 7, 023 (2022) · published 21 June 2022 | Toggle abstract · pdf

The initial phase of the inspiral process of a binary black-hole system can be described by perturbation theory. At the third post-Minkowskian order a two-loop double box graph, known as H-graph, contributes. In this talk we report how all master integrals of the H-graph with equal masses can be expressed up to weight four in terms of multiple polylogarithms. We also discuss techniques for the unequal mass case. The essential complication (and the focus of the talk) is the occurrence of several square roots.