Supersymmetry and Neutrinoless Double Beta Decay

Neutrinoless double beta decay ($\znbb$) induced by superparticle exchange is investigated. Such a supersymmetric (SUSY) mechanism of $\znbb$ decay arises within SUSY theories with R-parity non-conservation (\rp). We consider the minimal supersymmetric standard model (MSSM) with explicit \rp terms in the superpotential (\rp MSSM). The decay rate for the SUSY mechanism of $\znbb$ decay is calculated. Numerical values for nuclear matrix elements for the experimentally most interesting isotopes are calculated within pn-QRPA. Constraints on the \rp MSSM parameter space are extracted from current experimental half-life limits. The most stringent limits are derived from data on $^{76}$Ge. It is shown that these constraints are more stringent than those from other low-energy processes and are competitive to or even more stringent than constraints expected from accelerator searches.