Correlating double-difference of charge radii with quadrupole deformation and B ( E 2 ) in atomic nuclei

A good linear correlation is found between the double-difference of charge radius $\ensuremath{\delta}{R}_{2p\ensuremath{-}2n}(Z,N)$ with that of quadrupole deformation data in even-even nuclei. This results in a further improved charge radius relation that holds in a precision of about $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ fm. The new relation can be generalized to the reduced electric quadrupole transition probability $B(E2)$ between the first ${2}^{+}$ state and the ${0}^{+}$ ground state, and the mean lifetime $\ensuremath{\tau}$ of the first ${2}^{+}$ state. Same correlations are also seen in global nuclear models such as Hartree-Fock-Bogoliubov (HFB-24) and relativistic mean field (RMF); however, they are not consistent with the experimental data.