Global analysis of J/psi suppression in cold nuclear matter

TL;DR

This paper provides a comprehensive analysis of J/psi suppression in cold nuclear matter, incorporating new experimental data and nuclear parton density functions to better understand the underlying effects in nucleus-nucleus collisions.

Contribution

It extends previous Glauber analysis by including recent PHENIX d-Au measurements and EPS08 nuclear PDFs, offering refined estimates of J/psi suppression mechanisms.

Findings

Increased J/psi absorption cross section from 3.5 to 5.4 mb.

Observed stronger x-dependence of nuclear modification ratios.

Shifted cross section values at different energy scales.

Abstract

Interpreting the J/psi suppression reported in nucleus--nucleus collisions at SPS and RHIC requires the quantitative understanding of cold nuclear matter effects, such as the inelastic rescattering of J/psi states in nuclei or the nuclear modification of parton densities. With respect to our former Glauber analysis, we include in the present work the new PHENIX d--Au measurements, and analyze as well all existing data using the EPS08 nuclear parton densities recently released. The largest suppression reported in the new PHENIX analysis leads in turn to an increase of sigma from 3.5 +/- 0.3 mb to 5.4 +/- 2.5 mb using proton PDF. The stronger x-dependence of the G^{A}/G^p ratio in EPS08 as compared to e.g. EKS98 shifts the cross section towards larger values at fixed target energies (x_2 ~ 0.1) while decreasing somehow the value extracted at RHIC (x_2 ~10^{-2}).