BFKL equation with running QCD coupling and HERA data

TL;DR

This paper develops a BFKL evolution approach with running QCD coupling to successfully describe HERA deep inelastic scattering data, revealing insights into non-perturbative effects and Pomeron interactions at low Q^2.

Contribution

The paper introduces a diffusion approximation with running coupling within BFKL evolution that accurately fits HERA data and provides new understanding of Pomeron interactions and non-perturbative physics.

Findings

Good fit to HERA data with $\\chi^2/d.o.f. \approx 1.3

Non-perturbative effects appear at $Q^2=0.25$ GeV^2

Shadowing corrections could be significant at higher energies

Abstract

In this paper we developed approach based on the BFKL evolution in $\ln\Lb Q^2\Rb$. 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 $Q^2 = 0.25\,GeV^2$; (ii) the scattering amplitude at $Q^2 = 0.25\,GeV^2$ 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.