Study of the neutrinoless double beta decay, 0νββ, includes a variety of problems of nuclear structure theory. They are reviewed here. The problems range from the mechanism of the decay, i.e. exchange of the light Majorana neutrino neutrino vesus the exchange of some heavy, so far unobserved particle. Next, the proper expressions for the corresponding operator are described that should include ...

nuclear level densities and spin cut-off factors have been deduced for nuclei in the mass region 24‹a‹63,from a microscopic theory, which includes nuclear pairing interaction. single particle levels for both seeger and nilsson potentials were used in the calcdations. level densities extracted from the theory are compared with their conesponding experimental values, it is found that the overall ...