Lawrence Berkeley National Laboratory

Understanding the effects of cold nuclear matter on J/psi production is a key requirement in order to interpret the J/psi suppression reported in heavy-ion collisions. Based on a Glauber model, the J/psi-nucleon inelastic cross section is determined from a statistical analysis of J/psi world data on nuclear targets. The global fit of all data gives sigmaJ/psiN = 3.4 +/- 0.2 mb, significantly smaller than previous estimates, yet the chi2 of the fit is pretty large, chi2/ndf = 1.5. A similar value, sigmaJ/psiN = 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 emphasize that the present uncertainties on gluon (anti)shadowing do not allow for a precise determination of sigmaJ/psiN. Finally, the possible energy dependence of the J/psi-nucleon inelastic cross section is investigated within this framework. No significant energy dependence of the J/psi-N interaction is observed.