Neutrinoless double-beta decay and realistic shell model calculationsONLINE ONLY

Neutrinoless double beta (0νββ) decay is an exceedingly rare and unique process that could reveal physics beyond the Standard Model and, as such, its search is currently amongst the major objectives of experimental physics. The observation of such decay could distinguish the fundamental nature of the neutrino, whether Dirac or Majorana, and determine the absolute scale of the neutrino masses. 

The rate of this process depends on the nuclear matrix element (M0ν) associated with the transition, and the fact that this can only be provided by theoretical calculations spurs the theoretical nuclear physics community to provide the most reliable calculations needed for the success of the experimental programs. It is in this way possible to discover or, at least, to put an upper threshold to the value of the effective neutrino mass ⟨mββ⟩. 

In this seminar I'll show the results obtained in the framework of the Realistic Shell Model (RSM) for the M0ν involved in the decay of few 0νββ-decay candidates, in a mass interval ranging from A = 48 up to A = 136, under the hypothesis of light-neutrino exchange.

This approach provides a microscopic description of the nucleus starting from the bare nucleon-nucleon potential without resorting to empirical adjustments. As well as most of the cases in literature, these results have been obtained within the limits of the closure approximation. Therefore, to estimate the uncertainties associated with this approximation I'll report also on the results obtained for two selected cases using a mixed method that enables to go beyond the closure approximation.