Related papers: Natural fermion mass hierarchy and mixings in fami…
We propose a top hypercharge model with gauge symmetry SU(3)_C x SU(2)_L x U(1)_1 x U(1)_2 where the first two families of the Standard Model (SM) fermions are charged under U(1)_1 while the third family is charged under U(1)_2. The U(1)_1…
Right handed neutrinos with mass of ${\cal O} \; (10^{12}-10^{13})$ GeV are required to implement the see-saw mechanism and generate neutrino masses capable of playing a role in structure formation. Moreover models of fermion masses often…
The electroweak unification group $G\equiv SU(2)_L\times U(1)_e\times U(1)_\mu\times U(1)_\tau$ in which each fermion multiplet has its own $U(1)$ factor was proposed in 1986 to get the neutrino mass matrix. In this paper, the gauge group G…
The recent evidence for neutrino oscillations stimulate us to discuss again the problem of fermion masses and mixings in gauge theories. In the standard model, several forms for quark mass matrices are equivalent. They become ansatze within…
Guided by the flipping principle, we propose a novel extension of the Standard Model based on a double right-handed $U(1)$ gauge symmetry. In this framework, all left-handed fermions are neutral, while right-handed fermions of the third…
In many extensions of the Standard Model, including a broad class of left-right symmetric and Grand Unified theories, the light neutrino mass matrix is given by the left-right symmetric seesaw formula $M_\nu = f v_L - \frac{v^2}{v_R} Y_\nu…
The atmospheric and solar neutrino oscillation data suggest hierarchical neutrino masses with at least one large mixing. The simplest see-saw models for reconciling the two features are U(1) extensions of the SM with flavour dependent gauge…
The problem of families, "Why are there three families of fermions?", is a long awaited question to be answered within a reasonable framework. We propose anti-SU($N$) groups for the unification of families in grand unification (GUT) groups,…
We present a supersymmetric model of fermion masses with SU(4)*SU(2)^2*U(1)_X gauge group with matter in fundamental and antisymmetric tensor representations only. The up, down, charged lepton and neutrino Yukawa matrices are distinguished…
Recently a new mechanism has been proposed to cure the problem of fermion mass hierarchy in the Standard Model (SM) model. In this scenario, all SM charged fermions other than top quark arise from higher dimensional operators involving the…
An extension of the Standard Model to the local gauge group SU(3)_c X SU(3)_L X U(1)_X as a family independent model is presented. The mass scales, the gauge boson masses and the masses for the spin 1/2 particles in the model are studied.…
A SUSY SO(10) $\times A_4$ GUT model is constructed for fermion masses and mixing by introducing a minimal set of low dimensional Higgs representations needed to break the guage symmetry down to $SU(3)_c \times U(1)_{em}$. The hierarchy of…
We consider a SU(5) x U(1)_F GUT-flavor model in which the number of effects that determine the charged fermions Yukawa matrices is much larger than the number of observables, resulting in a hierarchical fermion spectrum with no particular…
We consider the $L$-$R$ symmetric composite model for quarks and leptons where constituent preons possessing some local $SU(N)_{MF}$ metaflavor symmetry are bound by the chiral $SO(n)_{L}\times SO(n)_{R}$ gauge metacolor forces. The…
We show that both small mixing in the quark sector and large mixing in the lepton sector can be obtained from a simple assumption of universality of Yukawa couplings and the right-handed neutrino Majorana mass matrix in leading order. We…
We propose a simple model of the neutrino mass matrix which can explain the solar and atmospheric neutrino problems in a 3($\nu_L + \nu_R$) framework. Assuming that only two right-handed neutrinos are heavy and a Dirac mass matrix has a…
We proposed a viable and predictive model based on the $SU(3)_C \times SU(3)_L \times U(1)_X$ gauge symmetry, supplemented by the global $U(1)_{Lg}$ symmetry, the $S_4$ family symmetry and several auxiliary cyclic symmetries, which…
We consider a left-right symmetric model with an $SU(2)_L$ and an $SU(2)_R$ scalar doublet but without the scalar bidoublet. The charged fermion masses in this model are generated via a universal seesaw mechanism. We add a set of three…
We show that experimental results for the masses and mixing of the neutrinos can be understood naturally by a simple grand unification model of SU(5) coupled to N=1 supergravity. No right-handed neutrinos are included. The left-handed…
We study the fermion mass and mixing hierarchy problems within the context of the SU(5) 4+1d domain-wall brane model of Davies, George and Volkas. In this model, the ordinary fermion mass relations of SU(5) grand unified theories are…