Gluon saturation and Feynman scaling in leading neutron production

TL;DR

This paper extends the color dipole formalism to analyze leading neutron production in high-energy electron-proton collisions, demonstrating its potential to observe gluon saturation effects in future colliders.

Contribution

It introduces a novel application of the color dipole formalism to leading neutron production, incorporating various models for the dipole-pion scattering amplitude and analyzing model dependencies.

Findings

Successfully reproduces H1 leading neutron spectra

Shows potential to observe gluon saturation effects in future colliders

Analyzes model dependence of predictions

Abstract

In this paper we extend the color dipole formalism to the study of leading neutron production in $e + p \rightarrow e + n + X$ collisions at high energies and estimate the related observables, which were measured at HERA and may be analysed in future electron-proton ($ep$) colliders. In particular, we calculate the Feynman $x_F$ distribution of leading neutrons, which is expressed in terms of the pion flux and the photon-pion total cross section. In the color dipole formalism, the photon-pion cross section is described in terms of the dipole-pion scattering amplitude, which contains information about the QCD dynamics at high energies and gluon saturation effects. We consider different models for the scattering amplitude, which have been used to describe the inclusive and diffractive $ep$ HERA data. Moreover, the model dependence of our predictions with the description of the pion flux is analysed in detail. We show that the recently released H1 leading neutron spectra can be reproduced using the color dipole formalism and that these spectra could help us to observe more clearly gluon saturation effects in future $ep$ colliders.