Doubleβ-decay nuclear matrix elements and lepton conservation

The nuclear matrix elements involved in the double β-decay of ⁴⁸Ca, ¹³⁰Te, and ¹²⁸Te were calculated using realistic nuclear interactions and shell model nuclear wave functions. The double doorway state is not appreciably mixed in the ground state of the final nuclei. So the ground state transitions contain a small fraction of the sum rule. A lepton nonconservation parameter η10^-4 was deduced.NUCLEAR STRUCTURE Double β-decay nuclear matrix elements. Shell model, realistic interactions. Lepton conservation.