Neutrinoless double beta decay can constrain neutrino dark matter
  We examine how constraints can be placed on the neutrino component of dark matter by an accurate measurement of neutrinoless double beta ($0\nu\beta\beta$) decay and the solar oscillation amplitude. We comment on the alleged evidence for $0\nu\beta\beta$ decay. 
V. Barger, S.L. Glashow, D. Marfatia and K. Whisnant