The Pseudothreshold Expansion of the 2-loop Sunrise Selfmass Master Amplitudes

TL;DR

This paper derives the pseudothreshold expansion of two-loop sunrise master amplitudes with arbitrary masses by solving differential equations, providing explicit lowest terms of the expansion.

Contribution

It introduces a method to obtain the pseudothreshold expansion of two-loop sunrise amplitudes for arbitrary masses using differential equations.

Findings

Explicit lowest terms of the pseudothreshold expansion are presented.

A systematic approach to solve for amplitudes at pseudothreshold is developed.

Abstract

The values at pseudothreshold of two loop sunrise master amplitudes with arbitrary masses are obtained by solving a system of differential equations. The expansion at pseudothreshold of the amplitudes is constructed and some lowest terms are explicitly presented.