Forward parton-nucleus scattering at next-to-eikonal accuracy in the CGC

TL;DR

This paper derives next-to-eikonal corrections to gluon and quark propagators in high-energy scattering, enabling more precise calculations of particle production in proton-nucleus collisions.

Contribution

It provides the first comprehensive derivation of NEik corrections to gluon and quark propagators, including multiple interaction channels, for improved scattering process modeling.

Findings

Derived full NEik corrections to gluon propagator.

Computed inclusive quark and gluon production cross sections at NEik accuracy.

Extended the theoretical framework beyond the shockwave and static limits.

Abstract

We derive the full next-to-eikonal (NEik) corrections to the gluon propagator from before to after traversing a highly boosted gluon background field, including corrections both beyond the shockwave limit and beyond the static limit in particular. After summarizing the results of the full NEik corrections to the before-to-after quark propagator computed in our earlier works, we also derive the before-to-inside, inside-to-inside and inside-to-after quark and gluon propagators, which are building blocks to calculate high-energy scattering processes at NEik order. Using these results and also including the NEik corrections that stem from interactions with the target via t-channel quark exchanges, we compute inclusive cross sections for quark and gluon production at forward rapidities in quark-nucleus and gluon-nucleus scatterings at NEik accuracy.