  If the electron neutrino has an effective nonzero Majorana mass, then
neutrinoless double beta decay will occur. However, the latter is possible also
with a negligible neutrino mass. We show how this may happen in a simple model
of scalar diquarks and dileptons. This possibility allows neutrino masses to be
small and hierarchical, without conflicting with the possible experimental
evidence of neutrinoless double beta decay.

High Energy Physics - Phenomenology