Canonical Seesaw Mechanism in Electro-Weak SU(4)L x U(1)Y Models

In this paper we prove that the canonical seesaw mechanism can naturally be implemented in a particular class of electro-weak SU(4)L x U(1)Y gauge models. The resulting neutrino mass spectrum is determined by just tuning a unique free parameter 'a' within the algebraical method of solving gauge models with high symmetries. All the Standard Model phenomenology is preserved, being unaffected by the new physics occuring at a high breaking scale m ~ 10^11GeV.Comment: 12 pages, 1 Table, no figure

Boson mass spectrum in SU(4)L⊗U(1)YSU(4)_L\otimes U(1)_Y model with exotic electric charges

The boson mass spectrum of the electro-weak \textbf{$SU(4)_{L}\otimes U(1)_{Y}$} model with exotic electric charges is investigated by using the algebraical approach supplied by the method of exactly solving gauge models with high symmetries. Our approach predicts for the boson sector a one-parameter mass scale to be tuned in order to match the data obtained at LHC, LEP, CDF.Comment: 12 pages, 1 Table with numerical estimates and 1 Figure added, mistaken results correcte

Neutrino Mass Squared Differences in the Exact Solution of a 3-3-1 Gauge Model without Exotic Electric Charges

The mass splittings for the Majorana neutrinos in the exact solution of a particular 3-3-1 gauge model are computed here in detail. Since both $\sin^{2}\theta_{13}\simeq0$ and the mass splittings ratio $r_{\Delta}\simeq0.033$ are taken into account, the analytical calculations seem to predict an inverted mass hierarchy and a mixing matrix with a texture based on a very close approximation to the bi-maximal mixing. The resulting formulas for the mass squared differences can naturally accomodate the available data if the unique free parameter ($a$) gets very small values ($\sim10^{-15}$). Consequently, the smallness of the parameter requires (according to our method) a large breaking scale $\sim10^{6}-10^{7}$ TeV in the model. Hence, the results concerning the neutrino mass splittings may lead to a more precise tuning in the exact solution of the 3-3-1 model of interest, being able - at the same time - to recover all the Standard Model phenomenology and predict the mass spectrum of the new gauge bosons $Z^{\prime},X,Y$ in accordance with the actual data. The minimal absolute mass in the neutrino sector is also obtained - $m_{0}\simeq0.0035$ eV - in the case of our suitable approximation for the bi-maxcimal mixing.Comment: 10 pages, no figure

The exact eigenstates of the neutrino mass matrix without CP-phase violation

In this paper we obtain the exact mass-eigenstates of the Majorana physical neutrinos. We start by taking into account a general $3\times3$ mass matrix without any CP-phase violation. It is then diagonalized by exactly solving an appropriate set of equations. The solution supplies straightforwardly the mass eigenvalues depending on the diagonal entries and mixing angles. Finally, the consequences of these analytical expressions are discussed assuming various phenomenological restrictions such as conserving the global lepton number $L=L_{e}-L_{\mu}-L_{\tau}$ and the $\mu-\tau$ interchange symmetry. The minimal absolute mass in the neutrino sector is also obtained since the two plausible scenarios invoked above are employed.Comment: 9 pages, no figure

Charged and Neutral Currents in a 3-3-1 Model with Right-Handed Neutrinos

The charged and the neutral currents are obtained by using a formal algebraical approach (developed and applied by the author) within the exact solution of a 3-3-1 gauge model with right-handed neutrinos. The entire Standard Model phenomenology is recovered without imposing any supplemental condition, but only by choosing an adecquate set of parameters from the very beginning of the calculus. A new and rich phenomenology regarding the particles and their currents occurs as well. The appealing feature of our results resides in the exact expressions of the currents which need not the adjustment usually due to the small mixing angle $\phi$ between neutral bosons $Z$ and $Z^{\prime}$ (like in the most of the papers in the literature treating the same issue). The required mixing was considered and aleready performed as an intermediate step by the solving method itself, since the physical eigenstates of those bosons were determined and then identified in the neutral currents.Comment: 14 pages, 1 Table, no figure

Conserving the lepton number Le−Lμ−LτL_{e}-L_{\mu}-L_{\tau} in the exact solution of a 3-3-1 gauge model with right-handed neutrinos

In this paper we consider a plausible scenario with conserved lepton number \textbf{$L=L_{e}-L_{\mu}-L_{\tau}$} within the framework of the exact solution of a particular 3-3-1 gauge model. We discuss what are the consequences of conserving this global leptonic symmetry from the viewpoint of the neutrino mass matrix constructed via special Yukawa terms (involving tensor products among Higgs triplets). We prove that the actual experimental data can naturally be reproduced by our scenario since soft breaking terms with respect to this lepton symmetry are properly introduced. As a consequence, our solution predicts for the neutrino sector the correct mass splitting ratio ($\Delta m_{12}^{2}/\Delta m_{23}^{2}\simeq0.033$), the inverted mass hierarchy, the correct values for the observed mixing angles ($\sin^{2}\theta_{23}\simeq0.5$ and $\sin^{2}\theta_{12}=0.31$)and the absolute mass of the lightest neutrino ($m_{0}\sim0.001$eV)independent of the breakung scale of the model.Comment: 10 pages, no figure

Neutrino mixing matrix in the 3-3-1 model with heavy leptons and A4A_4 symmetry

We study the lepton sector in the model based on the local gauge group $SU(3)_c\otimes SU(3)_L\otimes U(1)_X$ which do not contain particles with exotic electric charges. The seesaw mechanism and discrete $A_4$ symmetry are introduced into the model to understand why neutrinos are especially light and the observed pattern of neutrino mixing. The model provides a method for obtaining the tri-bimaximal mixing matrix in the leading order. A non-zero mixing angle $V_{e3}$ presents in the modified mixing matrix.Comment: 10 page

Charges and Mass Spectrum in the Pisano-Pleitez-Frampton 3-3-1 Gauge Model

The Pisano-Pleitez-Frampton 3-3-1 model is revisited here within the framework of the general method for solving gauge models with high symmetries. This exact algebraical approach - proposed several years ago by one of us - was designed to include a minimal Higgs mechanism that spontaneously breaks the gauge symmetry up to the universal $U(1)_{em}$ electromagnetic one and, consequently, to supply the mass spectrum and the couplings of the currents for all the particles in the model. We prove in this paper that this powerful tool, when is applied to the PPF 3-3-1 model, naturally recovers the whole Standard Model phenomenology and, in addition, predicts - since a proper parametrization is employed - viable results such as: (i) the exact expressions for the boson and fermion masses, (ii) the couplings of the charged and neutral currents and (iii) a plausible neutrino mass pattern. A generalized Weinberg transformation is implemented, while the mixing between the neutral bosons $Z$ and $Z^{\prime}$ is performed as a necessary step by the method itself. Some phenomenological consequences are also sketched, including the strange possibility that simultaneously $m(Z)=m(Z^{\prime})$ and $m(W)=m(V)$ hold.Comment: 20 pages, 1 Table, no figure

Large theta_13 from a model with broken L_e-L_mu-L_tau symmetry

Recent data in the neutrino sector point towards a relatively large value of the reactor angle, incompatible with a vanishing theta_ 13 at about 3 sigma. In order to explain such a result, we propose a SUSY model based on the broken L_e-L_mu-L_tau symmetry, where large deviations from the symmetric limit theta_12 = pi/4, tan(theta_23) \sim O(1) and theta_13 = 0 mainly come from the charged lepton sector. We show that a description of all neutrino data is possible if the charged lepton mass matrix has a special pattern of complex matrix elements.Comment: 9 pages, 2 figures. v2: comments and references added, as published in JHE