Heavy Ion Physics at Relativistic Energies

The main research topics are experimental studies of the properties of nuclear matter under extreme conditions. Nuclear matter as found in the center of atomic nuclei has a density of three hundred thousand billion (3x10¹⁴) times normal matter. When compressed further or heated, it exhibits various phases:

• At temperatures corresponding to the binding energy of a nucleon in a nucleus nuclear matter might change from a liquid to a gaseous phase - a process similar to boiling water at 100 degrees. Conditions of this kind might occur in supernovae explosions.
• At temperatures above about 170 MeV (100000 times hotter than in the interior of the sun) or at high densities, a phase transition from hadronic to quark-gluon matter takes place. The properties of matter in this extreme regime are crucial for the understanding of the early universe, where likely a transition from quarks and gluons to hadrons has occurred.

On earth, such temperatures can be probed only in collisions between nuclei at ultra-relativistic energies. The experiments related to highly excited and compressed matter are performed at GSI using the devices KaoS (photo top right), FOPI, and HADES. Our group performs also experiments related at CERN related to the quark-gluon phase transition, using the experiments CERES/NA45 and NA49. Presently,we perform a considerable amount of research and development of new detector technologies and highly-integrated electronics components for the new ALICE Experiment installed at the future LHC collider at CERN.

Prof. Dr. P. Braun-Munzinger, Priv. Doz. Dr. H. Oeschler