One-Loop Gauge Theory Amplitudes with an Arbitrary Number of External Legs

TL;DR

This paper reviews recent advances in calculating one-loop QCD amplitudes with many external legs, emphasizing unitarity and collinear behavior to construct accurate ansatze, especially for supersymmetric cases.

Contribution

It introduces a method to construct one-loop amplitudes with arbitrary external legs using unitarity and collinear limits, enhancing computational techniques in QCD.

Findings

Ansatz construction for arbitrary-leg one-loop amplitudes

Unique determination of supersymmetric amplitudes from cuts

Improved understanding of amplitude behavior in collinear limits

Abstract

We review recent progress in calculations of one-loop QCD amplitudes. By imposing the consistency requirements of unitarity and correct behavior as the momenta of two legs become collinear, we construct ansatze for one-loop amplitudes with an arbitrary number of external legs. For supersymmetric amplitudes, which can be thought of as components of QCD amplitudes, the cuts uniquely specify the amplitude.