One-loop Integral Coefficients from Generalized Unitarity

TL;DR

The paper presents a generalized unitarity-based method for calculating scalar integral coefficients in one-loop quantum field theory amplitudes, applicable to various theories including QCD and Electroweak.

Contribution

It introduces a novel approach that determines integral coefficients using unitarity and asymptotic behavior of cut momenta, applicable to arbitrary masses.

Findings

Works for arbitrary masses of external and internal legs

Applicable to QCD, Electroweak, and general quantum field theories

Provides a systematic way to compute one-loop integral coefficients

Abstract

I describe a method for determining the coefficients of scalar integrals for one-loop amplitudes in quantum field theory. The method is based upon generalized unitarity and the behavior of amplitudes when the free parameters of the cut momenta approach infinity. The method works for arbitrary masses of both external and internal legs of the amplitudes. It therefore applies not only to QCD but also to the Electroweak theory and to quantum field theory in general.