Nucleon distributions at nuclear periphery

The experimental ratios of the neutron to the proton densities at the nuclear periphery (similar or equal to half-density radius + 2.5 fm) determined using very low energy anti-proton annihilation studies are compared with the predictions of the semi-phenomenological model of the nucleon density distributions. The model incorporates correctly two physical requirements: the correct asymptotic behavior (r --> infinity) and the behavior near the center (r --> 0). The model gives a good account of the experiment. The results of the more sophisticated, microscopic mean field calculations like non-relativistic Hartree-Fock-Bogoliubov (HFB) with Skyrme type interactions though are qualitatively similar, the model density results are relatively closer to the experiment.