Density dependence of symmetry energy and neutron skin thickness revisited using relativistic mean field models with nonlinear couplings

The correlation between neutron skin-thickness of a nucleus with neutron excess and density slope parameter of symmetry energy is assessed as a function of density using relativistic mean-field models containing nonlinear couplings among different mesons. Models with larger skin were found to probe the density slope parameter even at suprasaturation densities, whereas models with smaller skin were observed to be sensitive only at specific subsaturation density, connected to the average density of nuclei. Possible reasons behind this density dependence are explored systematically. These results might be model specific, which need to be reassessed in other types of interactions existing in the literature. Nevertheless, extrapolating the predictions at high densities from models, which are optimized by data at saturation or subsaturation densities, needs to be handled with care.