Neutrino, Cosmos, and New Physics
  Observational manifestations of possible breaking of spin-statistics relation for neutrinos are considered. It is argued that bosonic neutrinos may form cosmological cold dark matter, improve agreement of BBN predictions with observations, make operative Z-burst model of ultra-high energy cosmic rays, etc. Restrictions for an admixture of bosonic component to neutrino which follow from double beta decay are discussed. 
A.D. Dolgov