Partial conservation of spin-isospin SU(4) symmetry in nuclei in connection with the rate of 2νββ decay
Rumyantsev O. A. , Urin M. G.
A new approach to calculating the amplitude for 2νββ decay of nuclei with well-developed nucleon pairing is proposed. This approach has been realized in its simplest version. It is based on the use of approximate conservation of spin-isospin 5ί7(4)στ symmetry in a description of charge-exchange excitations in the nuclei. The primary cause of the breaking of this symmetry is assumed to be the spin-orbit part of the mean field of the nucleus. In the approach proposed here, this spin-orbit part also determines the rate of 2νββ decay. Results calculated for decay half-lives with the help of the standard parameters of the mean field and of the interaction of quasiparticles are compared with existing experimental data. © 1995 American Institute of Physics.