COULOMB ENERGIES - AN ANOMALY IN NUCLEAR MATTER RADII

Nuclear matter raddi were calculated from measured Coulomb energy differences and charge radii. The Coulomb energy differences were taken between nuclear states that are members of an isobaric-spin multiplet. A significant anomaly in the radius of the excess nucleons was found. In the mirror pair 41Ca-41Sc, for instance, the known charge radius of the 40Ca core was used to extract the rms radius for the 41st nucleon. This radius is virtually the same as that of the 40Ca core, whereas any simple potential model would predict the 1f 7 2 orbit to be ∼ 20% larger than the average radius of the lower orbits. This qualitative effect is present in other mirror nuclei, and is also a feature of Coulomb energy differences from isobaric-spin analog states in heavier nuclei, for which the neutron excess is larger. © 1969.