What New Physics Can Double Beta Decay Experiments Hope to See?
  Double-beta decay experiments have been traditionally interpreted in terms of the Gelmini-Roncadelli triplet majoron model, which has been ruled out by LEP. We briefly survey here the kinds of physics to which these experiments might be sensitive in the light of the LEP constraints. We identify six broad categories of models, including some new categories which have not been previously considered. 
C.P. Burgess and J.M. Cline