A Simplest A4 Model for Tri-Bimaximal Neutrino Mixing

We present a see-saw $A_4$ model for Tri-Bimaximal mixing which is based on a very economical flavour symmetry and field content and still possesses all the good features of $A_4$ models. In particular the charged lepton mass hierarchies are determined by the $A_4\times Z_4$ flavour symmetry itself without invoking a Froggatt-Nielsen U(1) symmetry. Tri-Bimaximal mixing is exact in leading order while all the mixing angles receive corrections of the same order in next-to-the-leading approximation. As a consequence the predicted value of $\theta_{13}$ is within the sensitivity of the experiments which will take data in the near future. The light neutrino spectrum, typical of $A_4$ see-saw models, with its phenomenological implications, also including leptoproduction, is studied in detail.Comment: 20 pages, 2 figure

Neutrino masses and tribimaximal mixing in the minimal renormalizable supersymmetric SU(5) grand unified model with A4 flavor symmetry

We analyze all possible extensions of the recently proposed minimal renormalizable SUSY SU(5) grand unified model with the inclusion of an additional A4 flavor symmetry. We find that there are five possible cases but only one of them is phenomenologically interesting. We develop in detail such case and we show how the fermion masses and mixing angles come out. As a prediction we obtain the neutrino masses of order of 0.1 eV with an inverted hierarchy. © 2009 The American Physical Society

Toward a minimal renormalizable supersymmetric SU(5) grand unified model with tribimaximal mixing from A4 flavor symmetry

We address the problem of rationalizing the pattern of fermion masses and mixings by adding a non-Abelian flavor symmetry in a grand unified framework. With this purpose, we include an A4 flavor symmetry into a unified renormalizable supersymmetric grand unified theory SU(5) model. With the help of the "type II seesaw" mechanism we are able to obtain the pattern of observed neutrino mixings in a natural way, through the so-called tribimaximal matrix. © 2010 The American Physical Society