Related papers: A_4 model for the quark mass matrices
While a chiral fourth generation of quarks is almost ruled out from the data on Higgs boson production and decay at the Large Hadron Collider, vector-like quarks are still a feasible option to extend the fermionic sector of the Standard…
We propose a simple but realistic pattern of quark mass matrices at the string scale, which can be derived from orbifold models of superstring theory with no use of gauge symmetries. This pattern is left-right symmetric and preserves the…
An extension of the gauge group $SU(2)_L\otimes U(1)_Y$ of the standard model to the symmetry group $SU(4)_L\otimes U(1)_X$ (3-4-1 for short) is presented. The model does not contain exotic electric charges and anomaly cancellation is…
The U(1) flavor symmetry explains the large mixing of neutrinos while it leads to the unique texture for the quark mass matrices. It is remarked that U(1) symmetric mass matrices have the phenomenological defects. In the quark sector, the…
We perform a comprehensive analysis of the homogeneous finite modular group $\Gamma'_4\equiv S'_4$ which is the double covering of $S_4$ group. The weight 1 modular forms of level 4 are constructed in terms of Dedekind eta function, and…
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.
A very specific two-Higgs-doublet extension of the Glashow-Salam-Weinberg model for one generation of quarks is advocated for, in which the two doublets are parity transformed of each other and both isomorphic to the Higgs doublet of the…
We derive the canonical form of mixing of the mass eigenstates in the lepto-quark sector of the 4-generation Dirac-Kaehler extension of the SM (DK-SM) [1,2]. The 4 x 4 CKM matrix of DK-SM is expressed in terms two U(2) matrices. It depends…
Instead of anchoring the seesaw mechanism with the conventional heavy right-handed neutrino singlet, a small Majorana neutrino mass may be obtained just as well with the addition of a heavy triplet of leptons per family to the minimal…
We propose a multiscalar singlet extension of the singlet-triplet Higgs model capable of explaining the SM fermion mass spectrum and mixing parameters. Our model is based on the $\Delta \left( 27\right) $ family symmetry, supplemented by…
In the framework of a complete vector-like and universal gauged SU(3)_F family symmetry, we report a global region in the parameter space where this approach can account for a realistic spectrum of quark masses and mixing in a 4 x 4…
We study quark and lepton masses and mixings in a double covering of modular $A_4$ flavor symmetry in which we search for common solution of a single modulus $\tau$, applying chi-square numerical analysis under the as minimum framework as…
The Standard Model is extended by a SU(2)L singlet of vector leptoquarks. An additional SU(4) gauge symmetry between right-handed up quarks and right-handed leptons is introduced to render the model renormalizable. The arrangement is made…
We present a supersymmetric model of quark and lepton based on $S_4\times Z_3\times Z_4$ flavor symmetry. The $S_4$ symmetry is broken down to Klein four and $Z_3$ subgroups in the neutrino and the charged lepton sectors respectively.…
We perform a chi ^{2} fit at 95% CL to obtain model-dependent bounds to Z-Z' mixing angle theta and Z_2-mass in the framework of SU(3)_C X SU(3)_L X U(1)_X models with beta arbitrary. Using experimental results at the Z-pole and atomic…
We study an extension of the standard model based on the flavor symmetry A4 only. Neutrino Majorana mass terms arise from dimension five operator and charged lepton masses from renormalizable Yukawa couplings. We introduce three Higgs…
Inspired by the vector-like phenomenon of chiral gauge theories at short distances, we postulate that the $W^\pm$-gauge boson has a vector-like gauge coupling in the high-energy region, beside its purely right-handed gauge coupling observed…
Quark-lepton symmetric models are a class of gauge theories motivated by the similarities between the quarks and leptons. In these models the gauge group of the standard model is extended to include a ``color'' group for the leptons.…
We discuss a supersymmetric unified model based on a product gauge group SU(5)\times SU(5)\times SU(5), where the gauge symmetry breaking is achieved without the adjoint or higher-dimensional Higgs field, and the doublet-triplet splitting…
The forms of quark and lepton mass matrices are severely restricted in the $R_F$ parity model. We determine the form of the quark mass matrix first and derive the form of the neutrino mass matrix. For this to be consistent with the present…