Neutrino Masses and Mixing in Supersymmetric Models without $R$ Parity

Beschreibung

We study neutrino masses and mixing in Supersymmetric Models without $R$ parity and with generic soft Supersymmetry breaking terms. Neutrinos acquire mass from various sources: tree level neutrino--neutralino mixing, loop effects and non--renormalizable operators. Abelian horizontal symmetries (invoked to explain the smallness and hierarchy in quark parameters) replace $R$ parity in suppressing neutrino masses. We find lower bounds on the mixing angles: $\sin\theta_{ij} \gsim m(\ell_i^-)/m(\ell_j^-)$ ($i