Berlin 2005 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 4: Physik mit schweren Ionen
HK 4.4: Gruppenbericht
Freitag, 4. März 2005, 15:15–15:45, TU MA041
Determination of the Isoscalar and Isovector Equation-of-State in Heavy Ion Collisions* — •H.H. Wolter1, T. Gaitanos2, Ch. Fuchs3, M. Colonna2, M. Di Toro2, and R.A. Ionescu1,4 — 1Dept. Physik, Univ. of Munich — 2LNS, INFN, Catania — 3Inst. Theor. Physik, Univ. of Tübingen — 4NIPNE, Bucharest
A primary goal of heavy ion collisions at Fermi to relativistic energies has been the determination of hadronic equation-of-state (Eos) as a function of density, temperature, isospin or other flavors. In particular the isovector part has been of much interest recently because of the relevance for the structure of exotic nuclei and astrophysical systems, in particular neutron stars. Rather than test phenomenological Eos’s we have extensively investigated fields from relativistic, microscopic theories (Dirac-Brueckner) and recently also consistently the corresponding in-medium crosss sections. We find that generally flow data are reasonably well described, provided non-equilibrium effects in the effective interaction are taken into account. E.g. we are able to describe a recently proposed sensitive measure of the stopping (vartl) as proposed by FOPI. With respect to the density dependence of the isovector part, a crucial question in a relativistic formulation is the existence and importance of an scalar-isovector field. This can be parametrized in terms of a δ-meson, and leads to a stiffer isovector eos. We investigate various differential flow and stopping variables for protons/neutrons as well as for π± to find sensitive quantities to the isovector eos.
*supported by the BMBF, grant 06LM189