RHO-MESON COUPLING IN THE RELATIVISTIC MEAN-FIELD THEORY AND DESCRIPTION OF EXOTIC NUCLEI

The role of the isovector rho-meson coupling on the symmetry energy in the relativistic mean-field theory has been investigated. In a multi- dimensional parameter search for an appropriate force within the frame work of the non-linear sigmapmegarho model the rho-meson coupling has been found to have a significant effect on the neutron skin of nuclei. It has been shown that a low value of rho-meson coupling strength rem edies the defect of some of the existing parameter sets of providing a higher neutron skin thickness of nuclei. An extraordinarily good desc ription of highly proton- as well as neutron-rich exotic nuclei has be en found. It has been observed that the proper description of both pro ton-rich and neutron-rich nuclei is sensitive to the symmetry energy.