Origin of the Q^2-dependence of the DIS structure functions
Abstract
We consider in detail the Q^2 -dependence of the DIS structure functions, with Q being the virtual photon momentum. Quite often this dependence is claimed to be originated by the Q^2-dependence of the QCD coupling. This leads to the small-x asymptotics of the structure functions with Q^2 -dependent intercepts. We demonstrate that the DGLAP parametrization alpha_s = alpha_s (Q^2) is an approximation valid in the region of large x (where 2pq can be approximated by Q^2) only, providing the factorization scale is also large. Outside this region, the DGLAP parametrization fails, so alpha_s should be replaced by an effective coupling which is independent of Q^2 at small x. As a consequence, intercepts of the structure functions are independent of Q^2. Nevertheless, the small-x asymptotics of the structure functions explicitly depend on Q^2, even when the coupling does not depend on it. We also consider the structure functions at small Q^2 and give a comment on power-Q^2 corrections to the structure functions at large and small Q^2
Keywords
Cite
@article{arxiv.1212.3960,
title = {Origin of the Q^2-dependence of the DIS structure functions},
author = {B. I. Ermolaev and M. Greco and S. I. Troyan},
journal= {arXiv preprint arXiv:1212.3960},
year = {2015}
}
Comments
10 pp, no figures