Constructing QCD one-loop amplitudes

TL;DR

This paper presents a systematic method for calculating scalar bubble and triangle coefficients in one-loop QCD amplitudes using a unitarity bootstrap approach, focusing on behavior at infinity of the cut integrand.

Contribution

It introduces a general procedure for extracting integral coefficients in one-loop amplitudes via analyzing the integrand's behavior at infinity.

Findings

Provides a systematic way to determine scalar integral coefficients.

Enhances the efficiency of one-loop amplitude calculations.

Applicable to QCD and potentially other gauge theories.

Abstract

In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted after examining the behaviour of the cut integrand as the unconstrained parameters of a specifically chosen parametersiation of the cut loop momentum approach infinity.