Gravity induced neutrino-antineutrino oscillation: CPT and lepton number non-conservation under gravity

Abstract

We introduce a new effect in the neutrino oscillation phase which shows the neutrino-antineutrino oscillation is possible under gravity even if the rest masses of the corresponding eigenstates are same. This is due to CPT violation and possible to demonstrate if the neutrino mass eigenstates are expressed as a combination of neutrino and antineutrino eigenstates, as of the neutral kaon system, with the plausible breaking of lepton number conservation. For Majorana neutrinos, this oscillation is expected to affect significantly the inner edge of neutrino dominated accretion disks around a compact object by influencing the neutrino sphere which controls the accretion dynamics, and then the related type-II supernova evolution and the r-process nucleosynthesis. On the other hand, in early universe, in presence of various lepton number violating processes, this oscillation, we argue, might lead to neutrino asymmetry which resulted baryogenesis from the B-L symmetry by electro-weak sphaleron processes.