Anatomy of the differential gluon structure function of the proton from the experimental data on F_2p

I. P. Ivanov; N. N. Nikolaev

Paper

Anatomy of the differential gluon structure function of the proton from the experimental data on F_2p

Abstract

The use of the differential gluon structure function of the proton

introduced by Fadin, Kuraev and Lipatov in 1975 is called upon in many applications of small-x QCD. We report here the first determination of

from the experimental data on the small-x proton structure function

. We give convenient parameterizations for

based partly on the available DGLAP evolution fits (GRV, CTEQ & MRS) to parton distribution functions and on realistic extrapolations into soft region. We discuss an impact of soft gluons on various observables. The x-dependence of the so-determined

varies strongly with Q^2 and does not exhibit simple Regge properties. None the less the hard-to-soft diffusion is found to give rise to a viable approximation of the proton structure function F_{2p}(x,Q^2) by the soft and hard Regge components with intercepts Δ_{soft}=0 and Δ_{hard}\sim 0.4.