HARD PROBES OF DENSE MATTER

Abstract

Direct probes for the QGP must be hard enough to resolve sub-hadronic scales ($\ll {\text{la}}^{-1}$) and distinguish confined and deconfined media. This can be achieved by fast colour charges (jets) and heavy quark resonances (quarkonia). After a general survey, we study quarkonia as confinement probe and show in particular that confined matter is transparent, deconfined matter opaque to \J's.

Comments: 13 pages, plain TeX, figures available upon request from the author