The R-PARITY violating supersymmetric mechanism of neutrinoless double beta decay

Absence of neutrinoless double beta (0 nu beta beta) decay is usually interpreted in terms of an upper limit on the Majorana mass of the neutrino. However, in principle in any kind of extension of the standard model which allows lepton number violation at some level one can expect contributions to 0 nu beta beta decay, not necessarily related to the mass of the neutrino. Supersymmetric theories with explicit R-parity breaking are the most prominent example of this class of models. If R-parity violating SUSY is realized in nature, 0 nu beta beta decay can occur independent of neutrino properties. We have derived the decay rate for R-p MSSM 0 nu beta beta decay, including three diagrams not previously considered. A numerical calculation of the relevant nuclear structure matrix elements has been carried out. Using the experimental limit on the 0 nu beta beta decay half life of Ge-76 stringent limits on the strength of the R-parity violating interaction can be derived. A comparison with other bounds on R-parity violation, taken from the literature, shows that currently 0 nu beta beta decay gives the most stringent of all low-energy constraints and can even compete with the best available accelerator data.