## Abstract

The form of the leptonic mixing matrix emerging from experiment has, in the last few years, generated a lot of interest in the so-called tribimaximal type. This form may be naturally associated with the possibility of a discrete permutation symmetry (S_{3}) among the three generations. However, trying to implement this attractive symmetry has resulted in some problems and it seems to have fallen out of favor. We suggest an approach in which the S _{3} holds to first approximation, somewhat in the manner of the old SU(3) flavor symmetry of the three flavor quark model. It is shown that in the case of the neutrino sector, a presently large experimentally allowed region can be fairly well described in this first approximation. We briefly discuss the nature of the perturbations which are the analogs of the Gell-Mann-Okubo perturbations but confine our attention for the most part to the S_{3} invariant model. We postulate that the S_{3} invariant mass spectrum consists of nonzero masses for the (τb, t,) and zero masses for the other charged fermions but approximately degenerate masses for the three neutrinos. The mixing matrices are assumed to be trivial for the charged fermions but of tribimaximal type for the neutrinos in the first approximation. It is shown that this can be implemented by allowing complex entries for the mass matrix and spontaneous breakdown of the S_{3} invariance of the Lagrangian.

Original language | English |
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Pages (from-to) | 5875-5894 |

Number of pages | 20 |

Journal | International Journal of Modern Physics A |

Volume | 21 |

Issue number | 28-29 |

DOIs | |

Publication status | Published - Nov 20 2006 |

Externally published | Yes |

## Keywords

- Neutrino masses
- Neutrinoless double beta decay
- Permutation symmetry and electroweak interactions
- Tribimaximal mixing

## ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics
- Astronomy and Astrophysics