Confronting impact-parameter dependent model in next-to-leading order of perturbative QCD with combined HERA data

TL;DR

This paper applies a saturation model with impact-parameter dependence to HERA data, demonstrating good agreement and supporting its use for future collider predictions.

Contribution

It introduces an analytical solution for the BK equation with impact-parameter dependence and fits it to combined HERA data, enhancing the saturation model's predictive power.

Findings

Good agreement with HERA data on structure functions and vector meson production.

The model's impact-parameter dependence aligns with experimental observations.

Supports predictions for future experiments like EIC and LHeC.

Abstract

In this talk, we present the CGC/saturation approach of Ref.[C.~Contreras, E.~Levin, R.~Meneses and M.~Sanhueza,Eur. Phys. J. C 80 (2020) no.11, 1029] and its parameters determined from the combined HERA data. This model features an analytical solution for the non-linear Balitsky-Kovchegov (BK) evolution equation and the exponential behavior of the saturation momentum on the impact parameter $b$-dependence, characterized by $Q_s\propto \exp(-mb)$. We compare our results with experimental data at small-$x$, including the proton structure function $F_2$, charm structure function $F_2^{c\bar{c}}$, and exclusive vector meson production. The model shows good agreement across a wide kinematic range. Our findings support using this approach for reliable predictions in upcoming experiments like the Electron-Ion Collider (EIC) and the LHeC.