We present several possibilities offered by the reaction dynamics of dissipative heavy ion collisions to study in detail the symmetry term of the nuclear equation of state EOS. In particular we focus the attention on transport properties and fragment production mechanisms. We discuss some new features of instabilities in asymmetric nuclear matter, underlying in particular the link between the nature of unstable fluctuations and the properties of the interaction. Now chemical instabilities may appear as isoscalar-like unstable oscillations, similarly to mechanical instabilities, leading to the formation of a more symmetric liquid phase, surrounded by a neutron rich gas phase, the Isospin Distillation effect. We present numerical simulations of multifragmentation processes in, central heavy ion collisions at intermediate energies. In the same context, but in the case of semi-peripheral reactions, the dynamics of the so-called neck region is discussed. We show that in general the isospin dynamics plays an important role in all steps of the reaction, from prompt nucleon emission to primary cluster formation and eventually to sequential decays. Many observables appear rather sensitive to the isovector part of the nuclear EOS, in particular in more exclusive experiments. RI Baran, Virgil/A-8259-2011
Reaction dynamics with exotic nuclei
GRECO, VINCENZO
2002-01-01
Abstract
We present several possibilities offered by the reaction dynamics of dissipative heavy ion collisions to study in detail the symmetry term of the nuclear equation of state EOS. In particular we focus the attention on transport properties and fragment production mechanisms. We discuss some new features of instabilities in asymmetric nuclear matter, underlying in particular the link between the nature of unstable fluctuations and the properties of the interaction. Now chemical instabilities may appear as isoscalar-like unstable oscillations, similarly to mechanical instabilities, leading to the formation of a more symmetric liquid phase, surrounded by a neutron rich gas phase, the Isospin Distillation effect. We present numerical simulations of multifragmentation processes in, central heavy ion collisions at intermediate energies. In the same context, but in the case of semi-peripheral reactions, the dynamics of the so-called neck region is discussed. We show that in general the isospin dynamics plays an important role in all steps of the reaction, from prompt nucleon emission to primary cluster formation and eventually to sequential decays. Many observables appear rather sensitive to the isovector part of the nuclear EOS, in particular in more exclusive experiments. RI Baran, Virgil/A-8259-2011I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.