ISOBARIC ANALOG SPIN AND NUCLEAR SPECTRUM

Abstract

In investigating the effect of the coulomb interaction on the nuclear energy spectra, the isobaric analog spin is introduced as a plausible candidate to replace the isospin symmetry. The complete isomorphism of the isospin and analog spin representations is developed by using the group theoretical approach. The Hamiltonian in the analog spin representations is then set up and the relationships between the matrix elements in the two representations are established. Algebraic technique is developed to evaluate the analog-spin external partial width ar1d to minimize the analog spin admixings. Based on the analog spin symmetry the low lying spectra of various nuclei in the ds shells are projected by the standard spectral distribution method. Comparisons are made with the experimental results and with the calculations based on the isospin symmetry. In general, the spectra of the even-even nuclei are not much different in the two representations; however significant improvement (in comparison with empirical spectra) has been achieved for odd-A nuclei in the analog spin representation.