Eur. Phys. J. A 12, 421-433 (2001)
Testing Dirac-Brueckner models in collective flow of heavy-ion collisions
T. Gaitanos1, C. Fuchs2, H.H. Wolter1 and A. Faessler21 Sektion Physik der Universität München, Am Coulombwall 1, D-85748 Garching, Germany
2 Institut für Theoretische Physik der Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
christian.fuchs@uni-tuebingen.de
(Received: 8 January 2001 / Revised version: 31 October 2001 Communicated by P. Schuck)
Abstract
We investigate differential in-plane and out-of-plane flow observables
in heavy-ion reactions at intermediate energies from 0.2-2 AGeV
within the framework of relativistic BUU transport calculations. The
mean field is based on microscopic Dirac-Brueckner-Hartree-Fock (DB)
calculations. We apply two different sets of DB predictions, those
of ter Haar and Malfliet and more recent ones from the Tübingen group,
which are similar in general but differ in details. The
latter DB calculations exclude spurious contributions
from the negative-energy sector to the mean field which
results in a slightly softer equation of state and a
less repulsive momentum dependence of the nucleon-nucleus
potential at high densities and high momenta. For the application
to heavy-ion collisions in both cases non-equilibrium features
of the phase space are taken into account on the level of the
effective interaction. The systematic comparison to experimental
data favours the less repulsive and softer model.
Relative to non-relativistic approaches
one obtains larger values of the effective nucleon mass. This
produces a sufficient amount of repulsion to describe
the differential flow data reasonably well.
25.75.-q - Relativistic heavy-ion collisions.
25.75.Ld - Collective flow.
25.70.Mn - Projectile and target fragmentation.
21.65.+f - Nuclear matter.
© Società Italiana di Fisica, Springer-Verlag 2001
