# Gluon emission at small longitudinal momenta in the QCD effective action approach

## TL;DR

This paper investigates gluon emission vertices in the QCD effective action framework at small longitudinal momenta, revealing significant simplifications and their implications for reggeon interactions in high-energy collisions.

## Contribution

It introduces a simplified form of gluon emission vertices at small longitudinal momenta within the QCD effective action approach, enhancing understanding of reggeon interactions.

## Key findings

- Vertices simplify drastically at small longitudinal momenta
- Gluon emission occurs from a single reggeon coupled via multireggeon vertices
- Study of contributions in double and 2x2 elementary collisions

## Abstract

In the framework of the QCD effective action the vertices of gluon emission in interaction of reggeons are studied in the limit of small longitudinal momenta of the emitted gluon. It is found that the vertices drastically simplify in this limit so that the gluon becomes emitted from a single reggeon coupled to the projectile and target via multireggeon vertices. Contribution from this kinematical region is studied for double and 2x2 elementary collisions inside the composite projectile and target.