Nonlinear evolution in the re-summed next-to-leading order of perturbative QCD: Confronting the experimental data

Carlos Contreras,Eugene Levin,Michael Sanhueza

doi:10.1103/physrevd.104.116020

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 $\alpha_S$.

Highlights

The goal of this paper is to compare with the experimental (HERA) data the next-to-leading order approach (NLO) of Ref. [1]
That the data could be described, taking into account both the diffusion on lnðkT Þ, which stems from perturbative QCD, and the Gribov’s diffusion in impact parameters
We suggest a different way to account for the nonlinear corrections, than in Ref. [5], which leads to additional change of the NLO kernel of the evolution equation

Summary

Introduction

The goal of this paper is to compare with the experimental (HERA) data the next-to-leading order approach (NLO) of Ref. [1]. The goal of this paper is to compare with the experimental (HERA) data the next-to-leading order approach (NLO) of Ref. [1], we develop the approach in which we include the re-summation procedure, suggested in Refs. We suggest a different way to account for the nonlinear corrections, than in Ref. [5], which leads to additional change of the NLO kernel of the evolution equation. The advantage of our kernel of the BFKL equation [6,7], is that the scattering amplitude satisfies the high energy limits, which follows from the approach of Ref. We firmly believe that finding the correct NLO approximation for the nonlinear evolution is one of the most important and urgent problem in the theoretical description The advantage of our kernel of the BFKL equation [6,7], is that the scattering amplitude satisfies the high energy limits, which follows from the approach of Ref. [8] (see Refs. [9,10]) to the NLO Balitsky-Kovchegov (BK) [11] evolution [12,13,14,15,16,17,18].

Objectives

Results

Conclusion