Soft Factor Structure of MHV Amplitudes for Massless Charged Particles

TL;DR

This paper derives MHV amplitudes in massless electrodynamics, showing they are determined by soft photon behavior and can be expressed in a simple factorized form, with extensions to supersymmetry and gravity.

Contribution

It provides a straightforward derivation of MHV amplitudes based on soft factors and recursion relations, extending the understanding of amplitude structures in various theories.

Findings

Amplitudes are fully determined by their soft photon behavior.

MHV amplitudes admit a simple factorized form.

Recursion relations are used to prove the formulae.

Abstract

We present a simple derivation of MHV amplitudes in massless spinor and scalar electrodynamics. Working with permutationally invariant amplitudes, we show that they are fully determined by their soft photon behavior and admit a simple factorized form in terms of soft factors and lower-point amplitudes. We prove these formulae using recursion relations. Finally, we consider possible extensions of these results by looking at supersymmetric theories, amplitudes beyond the MHV sector, gravity, and theories with charged particles of higher spins.