${\beta }^2$ corrections to spherical EDF calculations for root-mean-square charge radii

Root-mean-square charge radii are discussed in terms of spherical Energy Density Functional (EDF) models corrected for quadrupole deformations. Comparisons between experiment and theory are made for the absolute radii of all even-even nuclei, for the isotonic shift between cadmium and tin isotopes, the isotopic shifts of the calcium isotopes and the isotonic shift for nuclei with $N=28$. We conclude that the data are well described in this approach, except for the sharp rise just after the neutron magic numbers.