J/\psi Suppression in Nucleus-Nucleus Collisions

Abstract

We propose a model for the production and suppression of J/\psi mesons in high-energy hadronic collisions. We factorized the process into a production of the $c\bar{c}$ pairs of relative momentum $k=k_c-k_{\bar{c}}$ convoluted with a transition probability from the produced $c\bar{c}$ pairs into the observed J/$\psi$ mesons. As the produced $c\bar{c}$ pairs exit the nuclear matter, the multiple scattering between the colored $c$ and $\bar{c}$ and the nuclear medium increases the square of the relative momentum between the $c$ and $\bar{c}, q^2=-k^2$, such that some of the $c\bar{c}$ pairs gain enough invariant mass to transmute into open charm states. With only one parameter, the amount of energy gained by the produced $c\bar{c}$ pair per unit length in the nuclear medium, our model can fit all observed J/\psi suppression data including recent NA50 data from Pb-Pb collisions.