J/ψ production and absorption in p + A and d+Au collisions

The level of “anomalous” charmonium suppression in high-energy heavy-ion collisions and its interpretation as a signal of quark-gluon plasma formation requires a robust understanding of charmonium production and absorption in proton-nucleus collisions. In a previous study we have shown that, contrary to common belief, the so-called J/ψ “absorption cross section”, , is not a “universal constant” but, rather, an effective parameter that depends very significantly on the charmonium rapidity and on the collision energy. Here we present ugraded Glauber calculations with the EPS09 parameterization of nuclear modifications of the parton densities. We confirm that the effective “absorption cross section” depends on the J/ψ kinematics and the collision energy. We also make further steps towards understanding the physics of the mechanisms behind the observed “cold nuclear matter” effects.