Nuclear expansion and symmetry energy of hot nuclei

Abstract

The decrease in the symmetry energy of hot nuclei populated in ${}^{58}$Ni + ${}^{58}$Ni, ${}^{58}$Fe + ${}^{58}$Ni and ${}^{58}$Fe + ${}^{58}$Fe reactions at beam energies of 30, 40, and 47 MeV/nucleon, as a function of excitation energy is studied. It is observed that this decrease is mainly a consequence of increasing expansion or decreasing density rather than the increasing temperature. The results are in good agreement with the recently reported microscopic calculation based on the Thomas-Fermi approach. An empirical relation to study the symmetry energy of finite nuclei in various mass region is proposed.

Comments: 10 pages, 2 figures