Diagrammatic proof of the BCFW recursion relation for gluon amplitudes in QCD

Abstract

We present a proof of the Britto Cachazo Feng Witten tree-level recursion relation for gluon amplitudes in QCD, based on a direct equivalence between BCFW decompositions and Feynman diagrams. We demonstrate that this equivalence can be made explicit when working in a convenient gauge. We exhibit that gauge invariance and the particular structure of Yang Mills vertices guarantee the validity of the BCFW construction.