Particle production in high-energy collisions beyond the shockwave limit

TL;DR

This paper calculates higher-order corrections to gluon production in high-energy collisions, revealing that nuclear effects are absent at NNE accuracy and identifying specific A^{2/3} corrections in two-gluon production.

Contribution

It introduces next to eikonal and next to next to eikonal corrections to the Lipatov vertex, advancing the theoretical understanding of gluon production beyond the shockwave approximation.

Findings

NNE corrections derived from electric field insertions into Wilson lines.

NNE corrections do not introduce nuclear effects in single gluon production.

Some two-gluon production contributions exhibit A^{2/3} dependence.

Abstract

We compute next to eikonal (NE) and next to next to eikonal (NNE) corrections to the Lipatov vertex due to a finite target thickness. These arise from electric field insertions into the eikonal Wilson lines. We then derive a $k_T$-factorization formula for single inclusive gluon production at NNE accuracy and find that nuclear effects are absent. We also analyze NNE corrections to two-gluon production where some of the contributions are found to exhibit corrections proportional to $A^{2/3}$.