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

Abstract

Background: The study of deep-inelastic reactions of nuclei provide a vehicle to investigate nuclear transport phenomena for a full range of equilibration dynamics. These inquires provide us the ingredients to model such phenomena and help answer important questions about the nuclear Equation of State (EOS) 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: Time-dependent Hartree-Fock (TDHF) method in full 3D is employed to calculate deep-inelastic reactions of $^{78}$Kr+$^{208}$Pb and $^{92}$Kr+$^{208}$Pb systems at 8.5~MeV$/A$. The impact parameter and energy-loss dependence of relevant observables are calculated. In addition, 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. Final properties of the fragments (charge, mass, scattering angle, kinetic energy) are computed. Conclusions: We find a smooth dependence of the energy loss, $E_\mathrm{loss}$, on the impact parameter for both systems. On the other hand the transfer properties for low $E_\mathrm{loss}$ values are very different for the two systems but become similar in the higher $E_\mathrm{loss}$ regime. The mean life time of the charge equilibration process, obtained from the final $(N-Z)/A$ value of the fragments, is shown to be $\sim 0.5$~zs. This value is slightly larger (but of the same order) than the value obtained from reactions at Fermi energies.