Related papers: $SU(4)_C \times SU(2)_L \times U(1)_R$ models with…
In this paper, we investigate lepton mass spectra, flavor mixing and CP violation with a modular $S^{}_4$ symmetry under the assumption that neutrinos are Dirac fermions. We find that the Majorana mass term can be forbidden by adjusting the…
A systematic study of the flavor group $T^{'}$ is presented in terms of a specific model which extends the standard model symmetry to $[SU(3) \times SU(2) \times U(1)]_{(local)} \times [T^{'} \times Z_2 \times Z_2^{'} \times…
We discuss a model based on dark sector described by non-Abelian $SU(2)_D$ gauge symmetry where we introduce $SU(2)_L \times SU(2)_D$ bi-doublet vector-like leptons to generate active neutrino masses and kinetic mixing between $SU(2)_D$ and…
We construct a supersymmetric SU(5) x A_4 flavour GUT model in which an inverse neutrino mass hierarchy is realised without fine-tuning of parameters. The model shares some properties with the normal hierarchy model which we presented in…
Modular symmetry offers the possibility to provide an origin of discrete flavour symmetry and to break it along particular symmetry preserving directions without introducing flavons or driving fields. It is also possible to use a weighton…
The $D_4$ flavor model based on $\mathrm{SU}(3)_C \otimes \mathrm{SU}(3)_L \otimes \mathrm{U}(1)_X$ gauge symmetry that aims at describing quark mass and mixing is updated. After spontaneous breaking of flavor symmetry, with the constraint…
To explain quark and lepton masses and mixing angles, one has to extend the standard model, and the usual practice is to put the quarks and leptons into irreducible representations of discrete groups. We argue that discrete flavor…
The lepton masses and mixings are studied on the basis of string inspired $SU(6)\times SU(2)_R$ model with global flavor symmetries. Provided that sizable mixings between lepton doublets $L$ and Higgsino-like fields $H_d$ with even R-parity…
We combine $SO(10)$ Grand Unified Theories (GUTs) with $A_4$ modular symmetry and present a comprehensive analysis of the resulting quark and lepton mass matrices for all the simplest cases. We focus on the case where the three fermion…
We discuss the connection between models of fermion masses and mixing involving a string-motivated flavor/generation U(1)$_A$ gauge symmetry and the $\mu$ term. We point out that in a certain class of such models the flavor physics can…
We propose a simple $U(2)$ model of flavor compatible with an $SU(5)$ GUT structure. All hierarchies in fermion masses and mixings arise from powers of two small parameters that control the $U(2)$ breaking. In contrast to previous $U(2)$…
We study the textures of SM fermion mass matrices and their mixings in a supersymmetric adjoint SU(5) Grand Unified Theory with modular $S_4$ being the horizontal symmetry. The Yukawa entries of both quarks and leptons are expressed by…
We study a Zee model applying a modular $A_4$ symmetry in supersymmetry framework, where we construct our lepton model as minimum modular weight as possible. We show our predictions on phases and neutrino masses through numerical analysis.…
A model in which quarks and leptons consist of three "more elementary" particles of spin 1/2 is proposed. A gauge field theory with SU(4) symmetry that corresponds to this model predicts the existence of two new bosons.
We propose a model for the quark masses and mixings based on an A_4 family symmetry. Three scalar SU(2) doublets form a triplet of A_4. The three left-handed-quark SU(2) doublets are also united in a triplet of A_4. The right-handed quarks…
Flavor violating processes in the quark and lepton sectors are investigated within a realistic supersymmetric $SO(10)\times A_4$ grand unification model. By employing exotic heavy fermion fields, this model successfully describes various…
We study the predictions for CP phases and absolute neutrino mass scale for broad classes of models with a U(2) flavor symmetry. For this purpose we consider the same special textures in neutrino and charged lepton mass matrices that are…
We propose a model based on modular $A_4$ symmetry containing a dark matter candidate, realizing radiatively induced neutrino mass at one-loop level. One finds that stability of dark matter candidate can be assured by nonzero value of…
In the $SU(3)_C \times SU(2)_L \times SU(2)_R \times U(1)_{(B-L)/2}$ extension of the standard model, a minimal (but asymmetric) scalar sector consists of one $SU(2)_R \times U(1)_{(B-L)/2}$ doublet and one $SU(2)_L \times SU(2)_R$…
In recent lattice calculations it has been discovered that mesons upon truncation of the quasi-zero modes of the Dirac operator obey a symmetry larger than the $SU(2)_L \times SU(2)_R\times U(1)_A$ symmetry of the QCD Lagrangian. This…