Neutrinoless Double Beta Decay with Negligible Neutrino Mass
  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. 
Biswajoy Brahmachari (Saha Inst., Kolkata), Ernest Ma (UC Riverside)