A systematic study of J/ψ suppression in cold nuclear matter

Understanding the effects of cold nuclear matter on J/ψ production is a key requirement for interpreting the J/ψ suppression reported in heavy-ion collisions. Based on a Glauber model, the J/ψ-nucleon inelastic cross section is determined from a statistical analysis of the J/ψ world data on nuclear targets. The global fit of all data gives σJ/ψN=3.4±0.2 mb, significantly smaller than previous estimates, yet the χ2 of the fit is pretty large, χ2/ndf=1.5. A similar value, σJ/ψN=3.5±0.2±1.7 mb, is obtained when the De Florian-Sassot modifications of the nuclear parton densities are included in the analysis, although we emphasise that the present uncertainties on gluon (anti-)shadowing do not allow for a precise determination of σJ/ψN. Finally, the possible energy dependence of the J/ψ-nucleon inelastic cross section is investigated within this framework. No significant energy dependence of the J/ψ-N interaction is observed. (orig.)