Dresden 2000 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 8: Theorie II
HK 8.6: Vortrag
Montag, 20. März 2000, 18:00–18:15, B 81
Formation of few-body clusters in nuclear matter — •M. Beyer1, P. Danielewicz2, C. Kuhrts1, G. Röpke1, W. Schadow3, P. Schuck4, and S. A. Sofianos5 — 1U Rostock — 2NSCL, E.-Lansing — 3TRIUMF, Vancouver — 4ISN, Grenoble — 5U Pretoria
The general focus is on correlations in interacting Fermi
systems. Correlations lead to pairing, bound states,
superconductivity, superfluidity, Bose-Einstein condensation etc.,
depending on the temperature and density of the system. The
description of such phenomena is particularly challenging, since the
quasi-particle picture reaches its limits. The framework to treat such
strongly correlated many-body systems (generally in a nonequilibrium
situation) is provided by the cluster expansion or Dyson equation
approach.
We apply a medium modified few-body theory to evaluated the properties
of light clusters (deuteron, triton, α-particle) in nuclear
matter. Solving an in-medium AGS-equation we calculate the shift of
bound state energies as well as the modification of reaction rates. As
a special effect the disappearance of bound states in dense matter
(Mott effect) is discussed.
These results are applied to calculated the time evolution of
expanding nuclear matter as produced, e.g., in heavy ion collisions.
Using a Boltzmann-Uehling-Uhlenbeck (BUU) approach the coupled
equations for the nucleon and deuteron distribution functions are
solved taking into account the medium dependence of the reaction rates
(Nd→ NNN, …). The results are compared with other
approaches and the experimental data.