beta beta 2 nu decay in Ca-48 - art. no. 055503

A schematic study of the beta beta2 nu decay of Ca-48 is made in a shell-mo del approach. The emphasis is especially put on the role of the spin-orbit potential in relation with the contribution of other terms in the strong in teraction. This is discussed with a particular attention to the behavior of these ones under the SU(4) symmetry. Different methods in calculating the transition amplitude are also looked at with the aim to determine their rel iability and, eventually, why they do not work. Further aspects relative to the failure of the operator expansion method to reproduce the results of m ore elaborate calculations are examined.