The ratio of
A figure ( GIF file of 7.3KB or PS file of 32KB ) shows the dependence of the anisotropy of the proton and the neutron skins on the quadrupole deformation parameter delta. For each ground or first-excited solution having nucleon skins, a symbol is put at a point whose abscissa is delta and its ordinate the skin thickness in the symmetry axis subtracted by that in the equatorial plane. The circle (plus) symbol is used for nuclei with A < = 100 ( > 100). The solid line is the result of a least-square fitting, while two dash lines correspond to twice as large mean-square deviation as the minimum value and can be used to judge the quality of the fitting.
For neutron skins, there is a tendency that the skin is thicker in the symmetry axis than in the equatorial plane for oblate deformations and vice versa for prolate deformations: The neutron skin tends to make density more spherical.
For protons, it is an interesting question whether the Coulomb repulsion between protons can reverse the trend in such a way that the proton skin promotes deformation. However, one cannot see any clear tendency in the right-hand side of the figure, mainly because the number of points are fewer (heavy nuclei do not have proton skins).
