QCD effective charge and the structure function $F_{2}$ at small-$x$

TL;DR

This paper investigates the infrared behavior of the QCD effective charge and its impact on the structure function F2 at small-x, demonstrating good agreement with HERA data through a generalized DAS approximation and a dynamical gluon mass.

Contribution

It introduces a consistent approach using a dynamical gluon mass and an effective charge to describe F2 at small-x within the generalized DAS approximation.

Findings

Good agreement with HERA data on F2 at small-x

Infrared behavior of the effective charge influences the gluon mass

Proposed ansatz for the effective coupling beyond leading order

Abstract

We study infrared contributions to the QCD description of the HERA data on the structure function $F_{2}$ within the \textit{generalized} DAS approximation. We argue that this approximation is a natural one and consistent with the phenomenon of dynamical mass generation in QCD. The investigation is performed at next-to-leading order by using the leading-twist expansion of $F_{2}(x,Q^{2})$ and by adopting an effective charge whose finite infrared behavior is constrained by a dynamical gluon mass. We propose one ansatz for the behavior of this effective coupling beyond leading order. The dependence of the experimental data on the infrared value of the effective charge is used in order to study the asymptotic behavior of the running gluon mass. The deep inelastic structure function $F_{2}$ obtained in this approach shows very good agreement with the experimental data.