Generalized Unitarity and Six-Dimensional Helicity

TL;DR

This paper integrates the unitarity method with six-dimensional helicity formalism to compute loop-level scattering amplitudes, demonstrating its effectiveness on QCD and N=4 super-Yang-Mills theory.

Contribution

It introduces a novel combination of unitarity and six-dimensional helicity formalism for amplitude calculations, including multiloop and nonplanar contributions.

Findings

Constructed dimensionally regularized QCD one-loop four-point amplitudes.

Confirmed four-loop four-point amplitude of N=4 super-Yang-Mills in six dimensions.

Discussed connections to Higgs infrared regulator and dual conformal symmetry.

Abstract

We combine the unitarity method with the six-dimensional helicity formalism of Cheung and O'Connell to construct loop-level scattering amplitudes. As a first example, we construct dimensionally regularized QCD one-loop four-point amplitudes. As a nontrivial multiloop example, we confirm that the recently constructed four-loop four-point amplitude of N=4 super-Yang-Mills theory, including nonplanar contributions, is valid for dimensions less than or equal to six. We comment on the connection of our approach to the recently discussed Higgs infrared regulator and on dual conformal properties in six dimensions.