Is the detailed shape of the nuclear charge distribution relevant to the ft values of superallowed Fermi transitions?

Abstract

Abstract The uniform nuclear charge distribution remains a satisfactory model for calculating electron radial wave functions and nuclear matrix elements even in the case of the superallowed Fermi transitions of light nuclei up to 54 Co, where high accuracy is needed to determine the vector coupling constant of nuclear β-decay. The modifications due to the deviation of the realistic charge distribution from this simple model are found to be smaller than previously thought and therefore are negligible, provided that the nuclear radius, which is the most important shape parameter, has its correct value (i.e. the r.m.s. radii of the realistic and the model distribution are the same). Moreover, the dependence on the nuclear radius is fairly small for the light nuclei under consideration.