MHV Techniques for QED Processes

TL;DR

This paper explores the application of MHV techniques, originally developed for Yang-Mills theories, to QED processes, demonstrating their effectiveness in calculating multiparticle scattering amplitudes at tree level.

Contribution

It extends MHV methods to abelian theories like QED, providing explicit calculations and comparisons with traditional techniques for processes involving multiple photons.

Findings

MHV techniques are applicable to QED processes.

Explicit calculations for up to 5 photons using MHV rules.

Comparison shows MHV methods are effective and consistent with traditional approaches.

Abstract

Significant progress has been made in the past year in developing new `MHV' techniques for calculating multiparticle scattering amplitudes in Yang-Mills gauge theories. Most of the work so far has focussed on applications to Quantum Chromodynamics, both at tree and one-loop level. We show how such techniques can also be applied to abelian theories such as QED, by studying the simplest tree-level multiparticle process, e^+e^- to n \gamma. We compare explicit results for up to n=5 photons using both the Cachazo, Svrcek and Witten `MHV rules' and the related Britto-Cachazo-Feng `recursion relation' approaches with those using traditional spinor techniques.