MHV techniques for QED processes

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 − → nγ. 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.