Global analysis of J/ψ suppression in cold nuclear matter
Interpreting the J/ψ suppression reported in nucleus–nucleus collisions at SPS and RHIC requires a quantitative understanding of cold nuclear-matter effects, such as the inelastic rescattering of J/ψ 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 we 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 σ J/ψN from 3.5±0.3 to 5.4±2.5 mb using the PDF of the proton. 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).
KeywordsGluon Distribution Inelastic Cross Section Tion Cross Section RHIC Energy NA50 Collaboration
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