Pontecorvo neutrino-antineutrino oscillations: theory and experimental limits

Abstract

We study Pontecorvo neutrino-antineutrino oscillations both in vacuum and in matter within a field theoretic approach, showing that this phenomenon can occur only if neutrinos have a Dirac-Majorana mass term. We find that matter effects suppress these oscillations and cannot explain the solar neutrino problem. On the contrary, a vacuum neutrino-antineutrino oscillations solution to this problem exists. We analyze this solution and available data from laboratory experiments giving stringent limits on $ν_e$ and $ν_μ$ Majorana masses.