Abstract
The presence of approximate electron number conservation and permutation symmetry of is shown to naturally provide bilarge neutrino mixing. First, the bimaximal neutrino mixing together with is guaranteed to appear owing to and then, the bilarge neutrino mixing together with arises as a result of a tiny violation of The observed mass hierarchy of is subject to another tiny violation of the electron number conservation. This scenario is realized in a specific model based on with two-loop radiative mechanism for neutrino masses. The radiative effects from heavy leptons contained in lepton triplets generate the bimaximal structure, and those from charged leptons, which break generate the bilarge structure together with To suppress dangerous flavor-changing neutral current interactions due to Higgs exchanges especially for quarks, this symmetry is extended to a discrete symmetry, which also ensures the absence of a one-loop radiative mechanism.
- Received 1 March 2004
DOI:https://doi.org/10.1103/PhysRevD.70.015011
©2004 American Physical Society