title: Scanning the quark-gluon plasma with charmonium.
abstract: We suggest the variation of charmonium production rate with Feynman x(F) in heavy ion collisions as a novel and sensitive probe for the properties of the created matter. Final state interactions with the comoving matter create a minimum at x(F) = 0, which is especially deep and narrow if a quark-gluon plasma is formed. While a strong effect is predicted at SPS, at the RHIC energy it overlaps with the expected peak formed by shadowing effects and needs comparison with pA data. We predict a steep dependence on centrality and suggest that this new probe is complementary to the dependence on transverse energy, and is more sensitive to a scenario of final state interactions.
authors.affiliation: Max Planck Institut für Kernphysik, Postfach 103980, D-69029 Heidelberg, Germany.
authors.forename: B Z
authors.initials: BZ
authors.lastname: Kopeliovich
authors.forename: A
authors.initials: A
authors.lastname: Polleri
authors.forename: J
authors.initials: J
authors.lastname: Hüfner