Evaluation of the degree of restoration of broken Wigner's SU(4) spin-isospin symmetry in nuclei

The Franzini-Radicati factor R was calculated on the basis of experimental data on the masses of nuclei in the mass-number range of 5 ≤ A ≤ 257. The values calculated for this factor made it possible to evaluate the degree of fulfillment of Wigner's SU(4) spin-isospin symmetry in nuclei. An expression for the factor R was obtained on the basis of Wigner's mass formula. This expression is isospin-dependent and takes into account odd-even variations in the mass. The formula for the factor R describes the separation of nuclei into threeWigner-type groups. The values calculated for the factor R were analyzed by the method of Student's t criterion, and it was inferred from the results of this analysis that only for nuclei having odd values of the mass number A and an isospin in the range of Tz ≥ 53/2 is broken Wigner's SU(4) spin-isospin symmetry restored, the confidence level being α = 0.01.