We study perturbations of exactly tri-bimaximal neutrino mixings under the assumption that they are coming solely from the charged lepton mass matrix. This may be plausible in scenarios where the mass generation mechanisms of neutrinos and charged leptons/quarks have a different origin. As a working hypothesis, we assume mass textures which may be ...

We analyze the effects of charged lepton corrections and renormalization group (RG) running on the low energy predictions of theories which accurately predict tri-bimaximal neutrino mixing at the high energy scale. In particular we focus on grand unified theory (GUT) inspired seesaw models with accurate tri-bimaximal neutrino ...

We present a supersymmetric T model for the tri-bimaximal neutrino mixing, and the complete flavor group is T�Z�Z. At leading order, the residual symmetry of the charged lepton sector is Z, and the T symmetry is broken completely in the neutrino sector. The charged lepton mass hierarchies are determined by the spontaneous breaking of the flavor symmetry, both the type I ...

In this Letter, we realize the tri-bimaximal mixing in the lepton sector in the context of minimal seesaw in which only two right-handed neutrinos are introduced, with the discrete group S4 as the family symmetry. In order to constrain the form of superpotential, a Z3 symmetry is also introduced. In the model, the mass matrices for charged leptons and right-handed neutrinos ...

Discrete non-abelian flavor symmetries give in a natural way tri-bimaximal (TBM) mixing as showed in a prototype model. However neutrino mass matrix pattern may be very different from the tri-bimaximal one if small deviations of TBM will be observed. We give the result of a model independent analysis for TBM neutrino mass pattern.

We investigate fermion mass matrices of the cascade form which lead to the tri-bimaximal mixing in the lepton sector. The cascade neutrino matrix predicts a parameter-independent relation among the observables, which are the neutrino mixing angles and mass squared differences. The relation predicts that the atmospheric neutrino mixing ...

We propose an extension of tri-bimaximal mixing to include a non-zero reactor angle ? while maintaining the tri-bimaximal predictions for the atmospheric angle ?=45� and solar angle ?=35�. We show how such tri-bimaximal-reactor mixing can arise at leading order from the (type I) see-saw mechanism with partially constrained sequential dominance. ...

Global fits to neutrino oscillation data are compatible with tri-bimaximal mixing pattern, which predict ?23 = ?/4, ? 12 = {sin}-1 (1&sqrt3; ) and ?13 = 0. We propose here to parametrize the tri-bimaximal mixing matrix VTBM by its hermitian generator HTBM using the exponential map. Then we use the exponential map to express the deviations from ...

We introduce a small correction term, ?M?, in the neutrino sector and examine whether a large ?13 and an almost maximal ?23 can simultaneously be obtained starting from the tri-bimaximal neutrino mixing. It is found that one can easily gain ?13?10�, which is favored by the recent T2K experiment, by taking account of the enhancement due to the degeneracy among three neutrino ...

We propose a realization of the so-called bimodal/schizophrenic model proposed recently. We assume S, the permutation group of four objects as flavor symmetry giving tri-bimaximal lepton mixing at leading order. In these models the second massive neutrino state is assumed quasi-Dirac and the remaining neutrinos are Majorana states. In the case of inverse ...

We discuss a neutrino mass model based on the S flavor symmetry within the minimal seesaw framework, in which only two right-handed neutrinos are introduced and transform as 2 under S. Although the model contains less free parameters compared to the typical seesaw models, it provides a successful description of the observed neutrino parameters, and in particular, a nearly ...

We write out the generic Dirac neutrino mass operator which possesses the Friedberg-Lee symmetry and find that its corresponding neutrino mass matrix is asymmetric. Following a simple way to break the Friedberg-Lee symmetry, we calculate the neutrino mass eigenvalues and show that the resultant neutrino mixing pattern is nearly tri-bimaximal. Imposing the ...

We construct a supersymmetric (SUSY) SU(5) model with the flavor symmetry S�Z�Z. Three generations of adjoint matter fields are introduced to generate the neutrino masses via the combined type I and type III see-saw mechanism. The first two generations of the 10-dimensional representation in SU(5) are assigned to be a doublet of S, the second family 10 is chose as the first component of the ...

We compute the mass spectrum of the fermionic sector of the Dirac�K�hler extension of the SM (DK-SM) by showing that there exists a Bogoliubov transformation that transforms the DK-SM into a flavor U(4) extension of the SM (SM-4) with a particular choice of masses and mixing textures. Mass relations of the model allow determination of masses of the 4th generation. Tree ...

We study the renormalization group running of the tri-bimaximal mixing predicted by the two typical S 4 flavor models at leading order. Although the textures of the mass matrices are completely different, the evolution of neutrino mass and mixing parameters is found to display approximately the same pattern. For both normal hierarchy and inverted hierarchy ...

We present a supersymmetric model of quark and lepton based on S�Z�Z flavor symmetry. The S symmetry is broken down to Klein four and Z subgroups in the neutrino and the charged lepton sectors, respectively. Tri-Bimaximal mixing and the charged lepton mass hierarchies are reproduced simultaneously at leading order. Moreover, a realistic pattern of ...

We discuss a particularly symmetric model of neutrino mixings where, with good accuracy, the atmospheric mixing angle ? is maximal, ?=0 and the solar angle satisfies sin?=1/3 (Harrison Perkins Scott (HPS) matrix). The discrete symmetry A is a suitable symmetry group for the realization of this type of model. We construct a model where the HPS matrix is ...

We propose new classes of models which predict both tri-bimaximal lepton mixing and a right-angled Cabibbo�Kobayashi�Maskawa (CKM) unitarity triangle, ??90�. The ingredients of the models include a supersymmetric (SUSY) unified gauge group such as SU(5), a discrete family symmetry such as A or S, a shaping symmetry including products of Z and Z ...

To address the issue of whether tri-bimaximal mixing (TBM) is a softly-broken hidden or an accidental symmetry, we adopt a model-independent analysis in which we perturb a neutrino mass matrix leading to TBM in the most general way but leave the three texture zeros of the diagonal charged lepton mass matrix unperturbed. We compare predictions for the ...

Motivated by recent hints in particle physics and cosmology, we study the realization of eV-scale sterile neutrinos within both the seesaw mechanism and flavor symmetry theories. We show that light sterile neutrinos can rather easily be accommodated in the popular A 4 flavor symmetry models. The exact tri-bimaximal mixing pattern is perturbed due to ...

Motivated by recent hints in particle physics and cosmology, we study the realization of eV-scale sterile neutrinos within both the seesaw mechanism and flavor symmetry theories. We show that light sterile neutrinos can rather easily be accommodated in the popular A_4 flavor symmetry models. The exact tri-bimaximal mixing pattern is perturbed due to ...

We compute the branching ratios for ??e?, ???? and ??e? in a supersymmetric model invariant under the flavour symmetry group A�Z�U(1, in which near tri-bimaximal lepton mixing is naturally predicted. At leading order in the small symmetry breaking parameter u, which is of the same order as the reactor mixing angle ?, we find that ...

We analyze the most general dimension-six effective Lagrangian, invariant under the flavour symmetry A�Z�U(1 proposed to reproduce the near tri-bimaximal lepton mixing observed in neutrino oscillations. The effective Lagrangian includes four-lepton operators that violate the individual lepton numbers in the limit of exact flavour symmetry and allow ...

Four different neutrino mass sum-rules have been analyzed: these frequently arise in flavor symmetry models based on the groups A, S or T?, which are often constructed to generate tri-bimaximal mixing. In general, neutrino mass can be probed in three different ways, using beta decay, neutrino-less double beta decay and cosmology. The general relations ...

Many neutrino experiments in the last few years have shown concrete evidence for neutrino mass and leptonic mixing; an indication of new physics beyond the standard model. In this thesis, we systematically study the flavor symmetry indicated by the low scale neutrino experiment data with the assumption that the seesaw mechanism is the reason for the light neutrino masses. In ...

The long baseline neutrino experiment, T2K, and the reactor experiment, Double Chooz will soon present new data. If we expect sin?_{13} to be 0.1 - 0.2, which is close to the present experimental upper bound, we should not persist in the paradigm of the tri-bimaximal mixing. We discuss breaking the tri-bimaximal mixing by adding a simple mass matrix, which ...

Starting from tri-bimaximal mixing at high scale, we investigate if it is possible to generate a sizable value of |Ue3|, while at the same time keeping solar neutrino mixing near its measured value, which is close to sin2 ?12 = 1/3 through renormalization group corrections. Generation of indicated values of |Ue3| approx 0.1 via this ...

We present a supersymmetric SO(10) grand unified theory (GUT) of flavor based on an S 4 family symmetry. It makes use of our recent proposal to use SO(10) with type II seesaw mechanism for neutrino masses combined with a simple ansatz that the dominant Yukawa matrix (the 10-Higgs coupling to matter) has rank one. In this paper, we show how the rank one model can arise within some plausible ...

We propose an A4 flavor-symmetric SU(3)?SU(2)?U(1) seesaw model where lepton number is broken spontaneously. A consistent two-zero texture pattern of neutrino masses and mixing emerges from the interplay of type-I and type-II seesaw contributions, with important phenomenological predictions. We show that, if the Majoron becomes massive, such seesaw scenario provides a viable ...

Reference proposed a flavor model based on the symmetry group S4, managing to describe fermion masses and mixings. The Weinberg operator has been used in order to provide the smallness of the neutrino masses, while a set of scalar fields, getting nonvanishing vacuum expectation values, spontaneously breaks down S4 and provides the tri-bimaximal pattern as the lepton ...