CVI. Isotopic spin selection rules. VIII: Charge independence and the comparison of isobaric triplets

Abstract

The experimentally-determined positions of the first T=1 states of self-conjugate nuclei up to ⁴⁰Ca are compared with their positions calculated from the known ground state mass differences of the T _z=+1 and T _z=0 isobars. The Coulomb correction is made in a completely automatic manner that does not involve an assumed nuclear radius but uses the experimental energy difference in the corresponding mirror pair. Close correspondence between calculated and experimental positions is found, the former being on the average higher by 35 kev. If this difference is taken to reflect a. departure from equality of the n-n and n-p singlet forces the latter is stronger by about 1% (square well). This is to be compared with the difference of 3% (square well) in the same sense found between p-p and n-p and n-p singlet forces from the zero energy scattering lengths.