prof.Johanna Stachel , prof. Peter Braun-Munziger

"Relativistic nuclear collisions - a quark matter factory" and "Quarkonia - messengers of deconfinement in quark matter"

Prof. Johanna Stachel (Universitaet Heidelberg) At high temperature and/or high density nuclear or hadronic matter is expected to undergo a phase transition. Quarks and gluons are freed from their confinement and chiral symmetry is restored. This is confirmed by calculations of QCD on a space-time lattice. Nuclear collisions at ultra-relativistic energies produce fireballs which contain such quark matter. The evidence for the production of quark matter will be presented and a discussion of the position of the phase boundary between normal hadronic matter and quark matter. Prof. Peter Braun-Munziger (GSI Darmstadt) Charmonia, bound states of charm and anticharm quarks, can be copiously produced in high energy nucleus-nucleus collisions. The experimentally observable yield depends on whether quark matter is formed, as well as on the degree of thermalization and deconfinement of charm quarks in the hot fireball. The various mechanisms for suppression and enhancement of charmonia will be discussed and relevant predictions compared with available data from the SPS and RHIC accelerator. Finally, the exciting prospects for charmonium measurements at the LHC will be presented.