A simple model for nuclear modification of parton distribution functions

TL;DR

This paper introduces a simple, analytically-based model for nuclear modifications of parton distribution functions, fitting experimental data to predict nuclear effects on quark and gluon densities across different nuclei.

Contribution

The model combines the rescaling approach with Fermi motion effects and implements scale dependence via DGLAP evolution, providing a new analytical framework for nuclear parton distributions.

Findings

Distinct shadowing and antishadowing behaviors for gluons and quarks.

Good agreement with experimental data on nuclear structure functions.

Predictions for unmeasured nuclei's parton distributions.

Abstract

A model for nuclear medium modification of parton densities is presented. The approach is based on the global analysis of available deep inelastic scattering data for different nuclear targets within the rescaling model combined with taking into account the effects of Fermi motion. The scale dependence is implemented into the DGLAP-evolved quark and gluon densities in a proton derived analytically at the leading order of QCD coupling. By fitting the rescaling parameters to experimental data on the ratio $F_2^A(x,Q^2)/F_2^{A^\prime}(x,Q^2)$ for several nuclear targets $A$ and $A^\prime$, we obtain redictions for nuclear parton distributions, even for unmeasured nuclei. The effects of nuclear modifications are investigated with respect to the mass number $A$. Our results highlight distinct shadowing and antishadowing behaviors for gluons and quarks.