A subtraction scheme for massive QED

TL;DR

This paper extends the FKS subtraction scheme to higher orders in perturbation theory for massive QED, enabling precise calculations of processes like muon decay with full mass dependence.

Contribution

It introduces a method to handle soft singularities at NNLO and beyond in massive QED calculations, expanding the applicability of subtraction schemes.

Findings

Successfully applied to NNLO QED corrections for muon decay

Provides a framework for higher-order calculations with massive fermions

Achieves full electron mass dependence in differential results

Abstract

We present an extension of the FKS subtraction scheme beyond next-to-leading order to deal with soft singularities in fully differential calculations within QED with massive fermions. After a detailed discussion of the next-to-next-to-leading order case, we show how to extend the scheme to even higher orders in perturbation theory. As an application we discuss the computation of the next-to-next-to-leading order QED corrections to the muon decay and present differential results with full electron mass dependence.