Loop amplitudes in gauge theories: modern analytic approaches

TL;DR

This paper reviews modern on-shell methods, especially unitarity cut techniques, for analytically computing loop amplitudes in gauge theories like Yang-Mills, QCD, and QED, highlighting their effectiveness in massless theories.

Contribution

It provides a comprehensive overview of unitarity-based methods for loop amplitude calculations, emphasizing their application to massless gauge theories.

Findings

Unitarity techniques simplify one-loop amplitude calculations.

Effective for massless theories like Yang-Mills, QCD, and QED.

Offers a unified framework for analytic loop computations.

Abstract

This article reviews on-shell methods for analytic computation of loop amplitudes, emphasizing techniques based on unitarity cuts. Unitarity techniques are formulated generally but have been especially useful for calculating one-loop amplitudes in massless theories such as Yang-Mills theory, QCD, and QED.