# Neutrino-antineutrino annihilation

1. May 16, 2006

### hellfire

As far as I know the usual extension of the standard model to include a massive neutrino implies a violation of the conservation of quantum numbers, this means the lepton number (since the neutrino is uncharged). During its propagation a massive left-handed neutrino can be regarded as a massive right-handed antineutrino with an appropiate Lorentz boost (as explained here). In that case, how can neutrino-antineutrino annihilation processes be explained? Do actually neutrinos and antineutrinos annihilate? It seams to me that there could exist an observer that regards the antineutrino as a neutrino, but still the neutrino as a neutrino.

Last edited: May 16, 2006
2. May 17, 2006

### Meir Achuz

Dirac neutrinos with mass behave like electrons with mass.
LH and RH refer to their weak interaction. Making a LT on a LH neutrino could give it positive helicity, but it would not be considered a RH particle or an anti-neutrino.

3. May 17, 2006

### hellfire

Thanks for the answer, but I think my question is rather about Majorana neutrinos. I think neutrino-antineutrino mixing is only possible with Majorana neutrinos. If the neutrino is a Majorana spinor, do annihilations take place?