Impact parameter profiles from nuclear shadowing ratio and applications to deuteron-gold collisions

TL;DR

This paper models impact parameter profiles of nuclear shadowing ratios using Gribov theory and applies them to analyze centrality-dependent observables in deuteron-gold collisions at high energy.

Contribution

It introduces a new impact parameter distribution model for nuclear shadowing based on Gribov theory, enhancing the understanding of centrality effects in nuclear collisions.

Findings

Impact parameter profiles of shadowing ratio are successfully modeled.

Application to d+Au collisions shows improved description of centrality dependence.

Provides a framework for incorporating spatial inhomogeneity in nuclear PDFs.

Abstract

While current nuclear parton distribution functions (nPDFs) from global fits to experimental data are spatially homogeneous, many experimental observables in nucleus-nucleus collisions are presented in terms of centrality cuts. These cuts can be related to impact parameter using the Glauber theory and it is thus usual in the description of such observables to convolute an assumed impact parameter distribution with the homogeneous nPDFs. In this study we use the Gribov theory of nuclear shadowing supplemented with information from diffraction to model the impact parameter distributions of nuclear shadowing ratio in the small-$x$ region. The modeled distributions are applied to the description of the centrality dependence of observables in deuteron-gold (d+Au) collisions at $\sqrt{s_{NN}} = 200$ AGeV.