Related papers: "Hidden" O(2) and SO(2) Symmetry in Lepton Mixing
We present a supersymmetric model with the flavour symmetry S4 x Z3 and a CP symmetry which are broken to a Z3 subgroup of the flavour symmetry in the charged lepton sector and to Z2 x CP (x Z3) in the neutrino one at leading order. This…
Three of the viable solutions of the solar neutrino problem are consistent with close to maximal leptonic mixing: $\sin^2\theta_{12}={1\over2}(1-\epsilon_{12})$ with $|\epsilon_{12}|\ll1$. Flavor models can naturally explain close to…
We show that minimal SO(10) Grand Unification models where the fermions have Yukawa couplings to only one (complex) {\bf 10} and one {\bf 126} of Higgs scalars lead to a very predictive neutrino spectrum. This comes about since the standard…
We study the possibility of generating non-zero reactor mixing angle $\theta_{13}$ by perturbing the $\mu-\tau$ symmetric neutrino mass matrix. The leading order $\mu-\tau$ symmetric neutrino mass matrix originates from type I seesaw…
We introduce three right-handed Majorana neutrinos and combine the type-I seesaw and inert doublet mechanisms. The resultant (active) neutrino mass matrix is divided into rank=1 and =2 parts with different energy scales. The different…
We discuss the possibility of flavor symmetries to explain the pattern of charged lepton and neutrino masses and mixing angles. We emphasize what are the obstacles for the generation of an almost maximal atmospheric mixing and what are the…
Constraints on the heavy sterile neutrino mixing angles are studied in the framework of a minimal supersymmetric ${\rm SO}(10)$ model with {\it double see-saw mechanism}. A new singlet matter in addition to the right-handed neutrinos is…
Within the framework of the two-Higgs Doublet Model (2HDM), we attempt to find some discrete, non-abelian flavour symmetry which could provide an explanation for the masses and mixing matrix elements of leptons. Unlike the Standard Model,…
In the context of a minimal extension of the Standard Model with three extra heavy right-handed neutrinos, we propose a model for neutrino masses and mixing based on the hipothesis of a complete alignment of the lepton mass matrices in…
We show how the nearly bi-maximal mixing scenario comes out naturally from gauged $SO(3)_{F}$ flavor symmetry via spontaneous symmetry breaking. An interesting relation between the neutrino mass-squared differences and the mixing angle,…
We present an $A4$-based model where neutrino masses arise from a combination of see-saw mechanisms. The model is motivated by several small mixing and mass parameters indicated by the data. These are $\theta_{13}$, the solar mass…
We propose a renormalizable multi-Higgs model with $A_{4}\otimes Z_{2}\otimes Z^{\prime}_{2}$ symmetry, accounting for the experimental deviation from the tribimaximal mixing pattern of the neutrino mixing matrix. In this framework we study…
We continue to investigate the minimal SO(10)xU(1)_H model which we proposed recently. Renormalization group analysis of the model results in natural predictions of quark-lepton masses and Kobayashi-Maskawa matrix along with neutrino…
We propose a viable model based on the $SU(3)_C\times SU(3)_L\times U(1)_X$ gauge group, augmented by the $U(1)_{L_g}$ global lepton number symmetry and the $\Delta(27) \times Z_3\times Z_{16}$ discrete group, capable of explaining the…
Assuming that neutrinos are not Majorana fermions and the right handed Dirac neutrino does not exist, we propose a model in which the second and the third generations of the leptons are composites, while the first generation is fundamental.…
We discuss two extensions of the Standard Model based on the seesaw mechanism and on non-abelian family symmetry groups O(2) and $D_4$, respectively. Both models have a twofold-degenerate neutrino Dirac mass matrix $M_D$, a Majorana mass…
We point out that the minimal seesaw model can provide a natural framework to accommodate tiny neutrino masses, while its experimental testability and notable predictiveness are still maintained. This possibility is based on the observation…
We study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and…
The presence of approximate electron number conservation and \mu-\tau permutation symmetry of S_2 is shown to naturally provide bilarge neutrino mixing. First, the bimaximal neutrino mixing together with U_{e3}=0 is guaranteed to appear…
The experimental data on atmospheric and solar neutrinos suggest that there is near-maximal mixing between \nu_\mu and \nu_\tau but that their masses are hierarchically separated. In models of Abelian horizontal symmetries, mixing of O(1)…