  We present a new contribution of the R-parity violating supersymmetry (SUSY)
to neutrinoless double beta decay via the pion exchange between decaying
neutrons. The pion coupling to the final state electrons is induced by the
R-parity violating SUSY interactions. We have found this pion-exchange
mechanism to dominate over the conventional two-nucleon one. The latter
corresponds to direct interaction between quarks from two decaying neutrons
without any light hadronic mediator like pion. The constraints on the certain
R-parity violating SUSY parameters are extracted from the current experimental
neutrinoless double beta decay half-life limit. These constraints are
significantly stronger than those previously known or expected from the ongoing
accelerator experiments.
