We study the energy-momentum and baryonic number conservation laws for quark-gluon plasma discontinuity transitions into hadron matter states. We find that the time-like shock hadronization of a supercooled quark-gluon plasma (when the normal vector to the discontinuity hypersurface is timelike) should take place. We consider some properties of this process, which is different from the standard...

Two decades ago Matsui and Satz suggested that Debye screening in the quark-gluon plasma would result in J/ψ suppression in heavy ion collisions. Much has happened in the subsequent years, and the picture of quark-gluon plasma at present is rapidly evolving – what does it imply for the J/ψ suppression? What are the recent RHIC and SPS results trying to tell us? What else has to be done? This ta...

In high-energy nuclear collisions, the new phase of the quark-gluon plasma is indicated by an anomalous increase in pressure, an excess of direct photon production, an excess of strangeness production, and an anomalous J/ψ suppression. We review these signatures and discuss how recent high-energy heavy-ion experiments at CERN are consistent with the production of the quark-gluon plasma in high-...

Assuming that ρ -mesons exist in a quark-gluon plasma at temperatures close to the QCD phase transition, we calculate the dilepton production rate from q-q̄ annihilation via a ρ -meson state using Vector Meson Dominance. The result is compared to the rates from direct q-q̄ annihilation and from π-π annihilation. Furthermore we discuss the suppression of low mass dileptons if the quarks assume an ...

While it is commonly believed that there is a direct transition from the hadronic to a quark gluon phase at high temperature, it would be prejudicial to rule out a sequence of dynamically generated intermediate scales. Using as guide, an effective lagrangian with unconfined gluons and constituent quarks, interacting with a chiral multiplet, we examine a scenario in which the system undergoes fi...

We estimate the survival probability of J/ψ in relativistic heavy-ion collisions, using both short-distance QCD and nuclear absorption mechanism. The suppression is found to be almost 100 percent for a thermally equilibrating quark-gluon plasma. The measurement of such a huge suppression of J/ψ may suggest the existence of a deconfined partonic medium, possibly a thermalised quark-gluon plasma,...

Data from the Relativistic Heavy Ion Collider over the last five years has led many to conclude that the medium created is not the expected quark gluon plasma (QGP), but rather a strongly coupled or strongly interacting quark gluon plasma (sQGP). We explore the meaning of this possible paradigm shift and the experimental and theoretical arguments that are associated with it. In this proceedings...

It has been predicted that dilepton production may be used as a quark-gluon plasma probe. We calculate the rapidity distributions of thermal dileptons produced by an evolving quark-gluon plasma assuming a longitudinal scaling expansion with initial conditions locally determined from the hadronic rapidity density. These distributions are compared with Drell-Yan production and semileptonic charm ...