Origin of the Q(2)-dependence of the DIS structure functions

Author:

Ermolaev, B. I.  Greco, M.  Troyan, S. I.  

Journal:

PHYSICS OF PARTICLES AND NUCLEI

Issue Date:

2013

Abstract(summary):

We consider in detail Q (2)-dependence of the DIS structure functions. Very 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) .

Page:

260---267