Interpretations of J/φ suppression

We review the two main interpretations of J/psi suppression proposed in the literature. The phase transition (or deconfining) scenario assumes that below some critical value of the local energy density (or of some other geometrical quantity which depends both on the colliding systems and on the centrality of the collision) there is only nuclear absorption. Above this critical value the absorptive cross section is taken to be infinite, i.e. no J/psi can survive in this hot region. In the hadronic scenario the J/psi dissociates due to both nuclear absorption and its interactions with co-moving hadrons produced in the collision. No discontinuity exists in physical observables. We show that an equally good description of this data is possible in either scenario.