Ward Identities for Amplitudes with Reggeized Gluons

TL;DR

This paper derives Ward identities for Green's functions of reggeized gluons in high energy QCD, enabling new amplitude representations and providing a novel derivation of the BFKL kernel.

Contribution

It introduces Ward identities based on gauge invariance for reggeized gluons, leading to new amplitude representations and a new derivation of the BFKL kernel.

Findings

Ward identities hold for reggeized gluon Green's functions

New representations of QCD amplitudes with reggeized gluons are derived

A novel derivation of the BFKL kernel is presented

Abstract

Starting from the effective action of high energy QCD we derive Ward identities for Green's functions of reggeized gluons. They follow from the gauge invariance of the effective action, and allow to derive new representations of amplitudes containing physical particles as well as reggeized gluons. We explicitly demonstrate their validity for the BFKL kernel, and we present a new derivation of the kernel.