QCD effective charge and the structure function [formula omitted] at small-x

Abstract

We study infrared contributions to the QCD description of the HERA data on the structure function F2 within the 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 F2(x,Q2) 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 F2 obtained in this approach shows very good agreement with the experimental data.