Dispersive Two-Loop Calculations: Methodology and Applications

TL;DR

This paper introduces a dispersive sub-loop insertion method for two-loop calculations, enabling precise evaluation of electroweak radiative corrections crucial for new physics searches in upcoming experiments.

Contribution

It presents a novel dispersive approach and a two-point function basis for two-loop integrals, improving computational efficiency for complex Feynman diagram evaluations.

Findings

Developed a dispersive sub-loop insertion technique.

Formulated two-loop integrals using two-point functions.

Applicable to a wide range of processes.

Abstract

As the new-generation precision experiments such as MOLLER and P2 look for physics beyond Standard Model, it is becoming increasingly important to evaluate the higher-order electroweak radiative corrections to a sub-percent level of uncertainty. However, due to propagators with different masses and higher-order tensor Feynman integrals, the two-loop calculations involving thousands of Feynman graphs become a demanding task requiring novel computational approaches. In this paper, we describe our dispersive sub-loop insertion approach and develop two-loop integrals using two-point functions basis which is applicable to wide range of processes.