Related papers: Neutrino Mass Matrix from S_4 Symmetry
We study the phenomenological implications of the modular symmetry $\Gamma(3) \simeq A_4$ of lepton flavors facing recent experimental data of neutrino oscillations. The mass matrices of neutrinos and charged leptons are essentially given…
We review the present state of and future outlook for our understanding of neutrino masses and mixings. We discuss what we think are the most important perspectives on the plausible and natural scenarios for neutrinos and what may have the…
Stimulated by Ma's idea which explains the tribimaximal neutrino mixing by assuming an A_4 flavor symmetry, a lepton mass matrix model is investigated. A Frogatt-Nielsen type model is assumed, and the flavor structures of the masses and…
Based on a new approach to quark and lepton masses, where the mass spectra originate in vacuum expectation values of O(3)-flavor 1+5 (gauge singlet) scalars, a neutrino mass matrix of a new type is speculated. The mass matrix is described…
We study neutrino masses and mixing in the context of flavor models with A4 symmetry, three scalar doublets in the triplet representation, and three lepton families. We show that there is no representation assignment that yields a…
We construct a neutrino model using the flavour group $S_4\times C_4 \times C_3\times C_2$ under the type-1 seesaw mechanism. The vacuum alignments of the flavons in the model lead to $\text{TM}_1$ mixing with $\sin…
To a first approximation, the quark mixing matrix has $\theta^q_{13} = \theta^q_{23} = 0$, whereas the lepton mixing matrix has $\theta^l_{23} = \pi/4$. We show how this structure may be understood if the family symmetry is $Q_8$, the…
We have investigated a neutrino mass matrix model without supersymmetry including three see-saw right-handed neutrinos around order $10^{12}$ GeV masses, aiming at a picture with all small numbers explained as being due to approximately…
The generalized $\mu$-$\tau$ interchange symmetry in the leptonic mixing matrix $U$ corresponds to the relations: $|U_{\mu i}|=|U_{\tau i}|$ with $i=1,2,3$. It predicts maximal atmospheric mixing and maximal Dirac CP violation given…
In the modular symmetry approach to neutrino models, the flavour symmetry emerges as a finite subgroup $\Gamma_N$ of the modular symmetry, broken by the vacuum expectation value (VEV) of a modulus field $\tau$. If the VEV of the modulus…
An understanding of the lepton masses within the framework of SUSY is presented. A family symmetry is introduced. Sneutrino VEV breaks this symmetry. The tau mass is due to the Higgs VEV, and muon mass purely from the sneutrino VEV. A…
Recently, Nishiura and the author have proposed a unified quark-lepton mass matrix model under a family symmetry U(3)$\times$U(3)$'$. The model can give excellent parameter-fitting to the observed quark and neutrino data. The model has a…
The problem of neutrino masses and mixing angles is analysed in a class of supersymmetric grand unified models, with SO(10) gauge symmetry and global U(2) flavour symmetry. Adopting the seesaw mechanism for the generation of the neutrino…
We propose a model which uses the seesaw mechanism and the lepton number $\bar L = L_e - L_\mu - L_\tau$ to achieve the neutrino mass spectrum $m_1 = m_2$ and $m_3 = 0$, together with a lepton mixing matrix $U$ with $U_{e3} = 0$. In this…
We have embedded the texture of the neutrino mass matrix with three families into the MaVaNs scenario. We take the power-law potential of the acceleron field and a typical texture of active neutrinos, which is derived by the D_4 symmetry…
The mass matrices of quarks have a simple structure if expressed in powers of the small parameter \sigma=(m_c/m_t)^{1/2}. If there is a close relation between quarks and leptons, one would expect similar structures for the lepton matrices…
We review recent developments in models of neutrino masses and mixing. Emphases are given to models based on finite group family symmetries from which the tri-bimaximal neutrino mixing can arise. In particular, we describe one recent model…
We show that large leptonic mixing occurs most naturally in the framework of the Sandard Model just by adding a fourth generation. One can then construct a small $Z_4$ discrete symmetry, instead of the large $S_{4L}\times S_{4R}$, which…
We discuss a minimal predictive see-saw model in which the right-handed neutrino mainly responsible for the atmospheric neutrino mass has couplings to (nu_e, nu_mu, nu_tau) proportional to (0,1,1) and the right-handed neutrino mainly…
We consider phenomenologically allowed structures of the neutrino mass matrix in the case of three light neutrino species. Constraints from the solar, atmospheric and reactor neutrino experiments as well as those from the neutrinoless…