Saturation QCD predictions with heavy quarks at HERA

TL;DR

This paper presents a QCD-based parametrization of the proton structure function at HERA, incorporating heavy quark effects, and finds no significant decrease in saturation momentum due to heavy quarks, aligning well with experimental data.

Contribution

It introduces a new QCD-inspired model for the proton structure function that includes heavy quark effects without reducing the saturation momentum, contrasting with previous models.

Findings

Good agreement with HERA data

Heavy quarks do not significantly decrease saturation momentum

Model constrains saturation dynamics directly from QCD

Abstract

The measurement of the proton structure function at HERA is often seen as a hint for the observation of saturation in high-energy QCD e.g. through the observation of geometric scaling. Accordingly, the dipole picture provides a powerful framework in which the QCD-based saturation models can be confronted to the data. In this paper, we give a parametrisation of proton structure function which is directly constrained by the dynamics of QCD in its high-energy limit and fully includes the heavy quark effects. We obtain a good agreement with the available data. Furthermore, to the contrary of various models in the literature, we do not observe a significant decrease of the saturation momentum due to the heavy quark inclusion.