Non-linear evolution in the re-summed next-to-leading order of perturbative QCD:\confronting the experimental data

TL;DR

This paper compares experimental HERA data with a re-summed NLO QCD approach, demonstrating successful data description including non-linear effects and impact parameter dependence, even at large coupling values.

Contribution

It introduces a re-summed NLO evolution approach that accurately models experimental data with fewer phenomenological parameters than previous models.

Findings

Successful description of HERA data with re-summed NLO corrections.

Inclusion of impact parameter dependence consistent with Froissart bound.

Effective modeling at large values of the strong coupling constant.

Abstract

In this paper we compare the experimental HERA data with the next-to-leading order approach (NLO) of Ref.[C.~Contreras, E.~Levin, R.~Meneses and M.~Sanhueza,Eur. Phys. J. C 80 (2020) no.11, 1029). This approach includes the re-summed NLO corrections to the kernel of the evolution equation, the correct asymptotic behaviour in the NLO at $\tau = r^2 Q^2_s \,\gg\,1$; the impact parameter dependence of the saturation scale in accord with the Froissarrt theorem as well as the non-linear corrections. In this paper, we successfully describe the experimental data with the quality, which is not worse, than in the leading order fits with larger number of the phenomenological parameters. It is demonstrated, that the data could be described, taking into account both the diffusion on $\ln(k_T)$, which stems from perturbative QCD, and the Gribov's diffusion in impact parameters. It is shown an ability to describe the data at rather large values of $\alpha_S$.