Related papers: Bimaximal mixing from lopsided neutrinos
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…
Under the assumption that the $2\leftrightarrow 3$ symmetry is broken only through phases, we give a systematical investigation of possible lepton mass matrix forms without referring to the explicit parameter values. The two types of the…
We have analyzed the possibility that the universal Yukawa coupling (democratic mass matrix) with small violations of Dirac and Majorana neutrinos can induce the large mixing of neutrinos through the seesaw mechanism. The possibility can be…
An overview is given of the experimental neutrino mixing results and types of neutrino models proposed, with special attention to the general features of various GUT models involving intra-family symmetries and horizontal flavor symmetries.…
The three electroweak doublet neutrinos $\nu_{e,\mu,\tau}$ of the Standard Model may acquire small seesaw masses, using either three Majorana fermion singlets $N$ or three Majorana fermion triplets $(\Sigma^+,\Sigma^0,\Sigma^-)$. It is…
We propose simple phenomenological lepton mass matrices which describe the three neutrinos almost degenerate in mass, leading to a very large mixing angle between $\nu_\mu$ and $\nu_\tau$, as consistent with a recent report on atmospheric…
Maximum mixing in atmospheric neutrino oscillation, as well as vanishing of the MNS matrix element $U_{e3}$, are consequences of a 2-3 symmetry, under which the neutrino mass matrix is invariant under the interchange of second and third…
We propose a particularly economical neutrino mass model, in which there are only two right-handed Majorana neutrinos of ${\cal O}(1)$ TeV and their masses are highly degenerate. Its novel Yukawa-coupling texture together with the seesaw…
The bounds on the neutrino mixing angles and CP Dirac phase for an SO(10) model with lopsided mass matrices, arising from the presence of ${\bf 16}_H$ and $\bar{\bf 16}_H$ Higgs representations, are studied by variation of the one real and…
Four zero neutrino Yukawa textures in a specified weak basis, combined with $\mu\tau$ symmetry and type-I seesaw, yield a highly constrained and predictive scheme. Two alternately viable $3\times3$ light neutrino Majorana mass matrices…
We discuss renormalization effects on neutrino masses and mixing angles in a supersymmetric string-inspired SU(4) X SU(2)_L X SU(2)_R X U(1)_X model, with matter in fundamental and antisymmetric tensor representations and singlet Higgs…
We discuss neutrino masses in the framework of a minimal extension of the minimal supersymmetric standard model (MSSM) consisting of an additional single right-handed neutrino superfield $N$ with a heavy Majorana mass $M$, which induces a…
We discuss two types of neutrino mass matrices which both give $\theta_{23} = 45^\circ$, i.e., a maximal atmospheric mixing angle. We review three models, based on the seesaw mechanism and on simple extensions of the scalar sector of the…
If the observed light neutrino masses are induced by their Yukawa couplings to singlet right-handed neutrinos, natural smallness of those renders direct collider tests of the electroweak scale neutrino mass mechanisms almost impossible both…
Best-fit values of recent global analyzes of neutrino data imply large solar neutrino mixing, vanishing U_{e3} and a non-maximal atmospheric neutrino mixing angle theta_{23}. We show that these values emerge naturally by the hypothesis of…
Using recent data on neutrino oscillations, we argue that a hierarchical solution for neutrino masses in a three-family context is possible, and that the masses of the tau and mu neutrinos are very nearly determined within that possibility.…
The flavor structure of the Standard Model may arise from random selection on a landscape. In a class of simple models, called "Gaussian landscapes," Yukawa couplings derive from overlap integrals of Gaussian zero-mode wavefunctions on an…
A novel scenario is presented within the Type-I seesaw mechanism in which no other beyond Standard Model fields except three heavy right handed neutrinos, have been considered. Light neutrino masses around sub eV scale, could be possible at…
It has recently been shown how tri-bimaximal neutrino mixing can be achieved, using the see-saw mechanism with constrained sequential dominance, through the vacuum alignment of a broken non-Abelian gauged family symmetry such as SO(3) or…
Recent atmospheric neutrino data at Super-Kamiokande suggest the large flavor mixing of neutrinos. Models for the lepton mass matrix, which give the near-maximal flavor mixing, are discussed in the three family model. Especially, details of…