Reaction Dynamics with Exotic Nuclei

Abstract

AbstractWe review the new possibilities offered by the reaction dynamics of asymmetricheavy ion collisions, using stable and unstable beams. We show that it represents arather unique tool to probe regions of highly Asymmetric Nuclear Matter (ANM) incompressed as well as dilute phases, and to test the in-medium isovector interactionfor high momentum nucleons. The focus is on a detailed study of the symmetryterm of the nuclear Equation of State (EOS) in regions far away from saturationconditions but always under laboratory controlled conditions.Thermodynamic properties of ANM are surveyed starting from nonrelativisticand relativistic effective interactions. In the relativistic case the role of the isovectorscalar δ-meson is stressed. The qualitative new features of the liquid-gas phase tran-sition, ”diffusive” instability and isospin distillation, are discussed. The results ofab-initio simulations of n-rich, n-poor, heavy ion collisions, using stochastic isospindependent transport equations, are analysed as a function of beam energy and cen-trality. The isospin dynamics plays an important role in all steps of the reaction,from prompt nucleon emissions to the final fragments. The isospin diffusion is alsoof large interest, due to the interplay of asymmetry and density gradients. In rela-tivistic collisions, the possibility of a direct study of the covariant structure of theeffective nucleon interaction is shown. Results are discussed for particle production,collective flows and iso-transparency.Perspectives of further developments of the field, in theory as well as in experi-ment, are presented.