arXiv:nucl-th/0010088·v1·Nuclear Theory
Transition to resonance-rich matter in heavy ion collisions at RHIC energies
L.V.Bravina (1,2)🇩🇪 · E.E.Zabrodin (1,2)🇩🇪 · M.Bleicher (3)🇺🇸 · S.A.Bass (4)🇺🇸 · M.Brandstetter(5)🇩🇪 · A.Faessler(1)🇩🇪 · C.Fuchs(1)🇩🇪 · W.Greiner(5)🇩🇪 · M.I.Gorenstein(5)🇺🇦 · S.Soff(6)🇩🇪 · H.Stoecker(5) (1 - Institut fuer Theoretische Physik, Tuebingen, Germany; 2 - Institute for Nuclear Physics, Moscow State University, Russia; 3 - Nuclear Science Division, Lawrence Berkeley Lab., USA; 4 - NSCL, Michigan State University, USA; 5 - Institut fuer Theoretische Physik,Frankfurt, Germany; 6 - GSI, Darmstadt, Germany)🇩🇪
Abstract
The equilibration of hot and dense nuclear matter produced in the central region in central Au+Au collisions at AGeV is studied within the microscopic transport model UrQMD. The pressure here becomes isotropic at fm/c. Within the next 15 fm/c the expansion of the matter proceeds almost isentropically with the entropy per baryon ratio . During this period the equation of state in the -plane has a very simple form, . Comparison with the statistical model (SM) of an ideal hadron gas reveals that the time of fm/ may be too short to attain the fully equilibrated state. Particularly, the fractions of resonances are overpopulated in contrast to the SM values. The creation of such a long-lived resonance-rich state slows down the relaxation to chemical equilibrium and can be detected experimentally.
Comments: Talk at the conference Strangeness'2000, to be published in J. of Phys. G