The Four Dimensional Helicity Scheme Beyond One Loop

TL;DR

This paper presents a method to convert scattering amplitudes from the four dimensional helicity scheme to the 't Hooft-Veltman scheme, including a new renormalization approach to handle evanescent contributions.

Contribution

It introduces a novel procedure for transforming amplitudes between schemes and a renormalization program addressing evanescent degrees of freedom beyond one loop.

Findings

Provides a systematic transformation method between schemes.

Develops a renormalization procedure for evanescent contributions.

Enables accurate amplitude calculations in different regularization schemes.

Abstract

I describe a procedure by which one can transform scattering amplitudes computed in the four dimensional helicity scheme into properly renormalized amplitudes in the 't Hooft-Veltman scheme. I describe a new renormalization program, based upon that of the dimensional reduction scheme and explain how to remove both finite and infrared-singular contributions of the evanescent degrees of freedom to the scattering amplitude.