BFKL equation with running QCD coupling and HERA data

Abstract

In this paper we developed approach based on the BFKL evolution in $\ln \text{Lb}{Q}^2\text{Rb}$. We show that the simplest diffusion approximation with running QCD coupling is able to describe the HERA experimental data on the deep inelastic structure function with good ${\chi }^2/d.o.f.\approx 1.3$. From our description of the experimental data we learned several lessons; (i) the non-perturbative physics at long distances started to show up at $Q^2=0.25Ge{V}^2$; (ii) the scattering amplitude at $Q^2=0.25Ge{V}^2$ cannot be written as sum of soft Pomeron and the secondary Reggeon but the Pomeron interactions should be taken into account; (iii) the Pomeron interactions can be reduced to the enhanced diagrams and, therefore, we do not see any needs for the shadowing corrections at HERA energies; and (iv) we demonstrated that the shadowing correction could be sizable at higher than HERA energies without any contradiction with our initial conditions.

Comments: 16pp,14 figures in eps.files