The MHV QCD Lagrangian

TL;DR

This paper derives a new formulation of light-cone gauge massless and massive QCD where the interaction vertices directly correspond to MHV amplitudes, simplifying calculations in quantum chromodynamics.

Contribution

It introduces a canonical transformation of QCD fields that produces an MHV-based Lagrangian, extending the MHV formalism to massive QCD.

Findings

Vertices are proportional to MHV amplitudes and valid off-shell

Explicit derivation for specific quark-gluon configurations

Generalization of the formalism to massive QCD

Abstract

We perform a canonical change of the field variables of light-cone gauge massless QCD to obtain a lagrangian whose terms are proportional up to polarisation factors to MHV amplitudes and continued off shell by the CSW prescription. We solve for this transformation as a series expansion to all orders in the new fields, and use this to prove that the resulting vertices are indeed MHV vertices as claimed. We also demonstrate how this works explicitly for the vertices with: two quarks and two gluons, four quarks, and a particular helicity configuration of two quarks and three gluons. Finally, we generalise the construction to massive QCD.