Role of parton shadowing in the comparison of p-A and A-A results on jpsi suppression at energies available at the CERN Super Proton Synchrotron

TL;DR

This paper examines how parton shadowing influences the baseline for J/psi suppression in heavy-ion collisions at CERN SPS energies, highlighting its impact on interpreting anomalous suppression signals.

Contribution

It provides a detailed analysis of parton shadowing effects on J/psi yield references in p-A and A-A collisions at SPS energies, which was previously not thoroughly quantified.

Findings

Parton shadowing significantly affects the reference J/psi yield in A-A collisions.

Shadowing effects vary with rapidity and centrality, influencing suppression interpretations.

Quantitative estimates of shadowing impact for In-In and Pb-Pb collisions are provided.

Abstract

The observation of an anomalous jpsi suppression in nucleus-nucleus collisions is one of the most important results of the SPS heavy-ion program. An essential ingredient in this result is the determination, obtained by studying p-A collisions, of effects not related with the formation of a deconfined medium. These effects are extrapolated to A-A collisions, determining a reference jpsi yield that is then compared with the measurements. In this article we investigate the role of parton shadowing on the determination of such a reference, and we calculate its effect for In-In and Pb-Pb collisions as a function of rapidity and centrality.