The Color Glass Condensate formalism, Balitsky-JIMWLK evolution and Lipatov's high energy effective action

TL;DR

This paper demonstrates that Lipatov's high energy effective action can reproduce quark and gluon propagators used in the Color Glass Condensate formalism, leading to a derivation of the Balitsky-JIMWLK evolution equation.

Contribution

It shows how to obtain relevant propagators from Lipatov's effective action and rederives the leading order Balitsky-JIMWLK equation within this framework.

Findings

Propagators can be derived from the effective action with a special gluonic field parametrization.

The derivation confirms the reggeized gluon as the logarithm of an adjoint Wilson line.

The approach reproduces key equations in high energy QCD formalism.

Abstract

We investigate the question whether Lipatov's high energy effective action is capable to reproduce quark and gluon propagators which resum interaction with a strong background field within high energy factorization. Such propagators are frequently employed in calculations within the Color Glass Condensate formalism, in particular when considering scattering of a dilute projectile on a dense target nucleus or nucleon. We find that such propagators can be obtained from the high energy effective action, if a special parametrization of the gluonic field is used, first proposed by Lipatov in the original publication on the high energy effective action. The obtained propagators are used to rederive from the high energy effective action the leading order Balitsky-JIMWLK evolution equation in covariant gauge. As an aside, our result confirms the definition of the reggeized gluon as the logarithm of an adjoint Wilson lines, proposed in the literature.