Transport properties of isospin asymmetric nuclear matter using the time-dependent Hartree-Fock method

Abstract

Background: The study of deep-inelastic reactions of nuclei provides a vehicle to explore nuclear transport phenomena for a full range of equilibration dynamics. These investigations provide us the ingredients to model such phenomena and help answer important questions about the nuclear equation of state and its evolution as a function of neutron-to-proton (N/Z) ratio.

Purpose: The motivation is to examine the real-time dynamics of nuclear transport phenomena and its dependence on N/Z asymmetry from a microscopic point of view to avoid any pre-conceived assumptions about the involved processes.

Method: The time-dependent Hartree-Fock (TDHF) method in full three dimensions is employed to calculate deep-inelastic reactions of 78Kr+208Pb and 92Kr+208Pb systems at 8.5 MeV/nucleon. The impact parameter and energy-loss dependence of relevant observables are calculated. In addition, the density-constrained TDHF method is used to compute excitation energies of the primary fragments. The statistical deexcitation code gemini is utilized to examine the final reaction products.

Results: The kinetic energy loss and sticking times as a function of impact parameter are calculated. The final properties of the fragments (charge, mass, scattering angle, and kinetic energy) are computed. Their evolution as a function of energy loss is studied and various intra-relations are investigated. The fragment excitation energy sharing is computed.

Conclusions: We find a smooth dependence of the energy loss, E loss, on the impact parameter for both systems. However, the transfer properties for low E loss values are very different for the two systems but become similar in the higher Eloss regime. The mean lifetime of the charge equilibration process, obtained from the final (N−Z)/A value of the fragments, is shown to be ∼0.5 zs. This value is slightly larger than (but of the same order as) the value obtained from reactions at Fermi energies. Show more