Narrow Results

Influences of the isospin-dependent in-medium nucleon–nucleon cross-section and momentum-dependent interaction (MDI) on the isoscaling parameter α are investigated for two central collisions ⁴⁰Ca + ⁴⁰Ca and ⁶⁰Ca + ⁶⁰Ca. These collisions are with isospin dependent quantum molecular dynamics in the beam energy region from 40 to 60 MeV/nucleon. The isotope yield ratio R₂₁(N, Z) for the above two central collisions depends exponentially on the neutron number N and proton number Z of isotopes, with an isoscaling. In particular, the isospin-dependent and MDI induce an obvious decrease of the isoscaling parameter α. The mechanism of the decreases of α by both and MDI are studied respectively.

In order to determine the equation of state in the isospin asymmetrical nuclear interactions, we have found the observables for extracting the information of them within the isospin-dependent quantum molecular dynamics in recent years. The several sensitive probes for extracting the information of the in-medium nucleon–nucleon cross section and the symmetry potential have found; meanwhile, their mechanisms are investigated in more details. The main point in this paper gives the summary for above probes and their outlook in the future.

A major goal of contemporary nuclear physics is to improve our knowledge of the nuclear matter equation of state (EoS). In particular, the EoS of isospin-asymmetric matter (that is, with unequal concentrations of protons and neutrons), is not well understood, mostly due to our limited knowledge of the symmetry energy. The latter reduces the binding energy in a nucleus with unequal number of protons and neutrons, and is crucial for understanding nuclear stability. We will review experimental, phenomenological and theoretical facts about the symmetry energy, with particular emphasis on analyzing how the various components of the nuclear force, in a microscopic model, contribute to this important quantity.

Exploring the isospin dependence of the nuclear matter is one of the main challenges of modern nuclear physics. The ab initio calculations are the proper tool for these investigations. Results of the Dirac-Brueckner-Hartree-Fock calculations for asymmetric nuclear matter, which are based on improved approximation schemes, are presented. Furthermore, the application to finite nuclei is discussed.