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Register a new userThe $Delta(27)$ flavor 3-3-1 model with neutral leptons
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2016
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We build the first 3-3-1 model based on the $Delta (27)$ discrete group symmetry, consistent with fermion masses and mixings. In the model under consideration, the neutrino masses are generated from a combination of type-I and type-II seesaw mechanisms mediated by three heavy right-handed Majorana neutrinos and three $SU(3)_{L}$ scalar antisextets, respectively. Furthermore, from the consistency of the leptonic mixing angles with their experimental values, we obtain a non-vanishing leptonic Dirac CP violating phase of $-frac{pi }{2}$. Our model features an effective Majorana neutrino mass parameter of neutrinoless double beta decay, with values $m_{beta beta }=$ 10 and 18 meV for the normal and the inverted neutrino mass hierarchies, respectively.
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We construct a 3-3-1 model based on non-Abelian discrete symmetry $T_7$ responsible for the fermion masses. Neutrinos get masses from only anti-sextets which are in triplets $underline{3}$ and $underline{3}^*$ under $T_7$. The flavor mixing patterns and mass splitting are obtained without perturbation. The tribimaximal form obtained with the breaking $T_7 rightarrow Z_3$ in charged lepton sector and both $T_7 rightarrow Z_3$ and $Z_3 rightarrow {mathrm{Identity}}$ must be taken place in neutrino sector but only apart in breakings $Z_3 rightarrow {mathrm{Identity}}$ (without contribution of $si$), and the upper bound on neutrino mass $sum_{i=1}^3m_i$ at the level is presented. The Dirac CP violation phase $delta$ is predicted to either $frac{pi}{2}$ or $frac{3pi}{2}$ which is maximal CP violation. From the Dirac CP violation phase we obtain the relation between Eulers angles which is consistent with the experimental in PDG 2012. On the other hand, the realistic lepton mixing can be obtained if both the direction for breakings $T_7 rightarrow Z_3$ and $Z_3 rightarrow {mathrm{Identity}}$ are taken place in neutrino sectors. The CKM matrix is the identity matrix at the tree-level.
We construct a $D_4$ flavor model based on SU(3)_C X SU}(3_L X U(1)_X gauge symmetry responsible for fermion masses and mixings. The neutrinos get small masses from antisextets which are in a singlet and a doublet under $D_4$. If the D_4 symmetry is violated as perturbation by a Higgs triplet under SU(3)_L and lying in {1} of D_4, the corresponding neutrino mass mixing matrix gets the most general form. In this case, the model can fit the experimental data in 2012 on neutrino masses and mixing. Our results show that the neutrino masses are naturally small and a little deviation from the tribimaximal neutrino mixing form can be realized. The quark masses and mixing matrix are also discussed. In the model under consideration, the CKM matrix can be different from the unit matrix. The scalar potential of the model is more simpler than those of the model based on $S_3$ and $S_4$. Assignation of VEVs to antisextets leads to the mixing of the new gauge bosons and those in the Standard Model. The mixing in the charged gauge bosons as well as the neutral gauge boson is considered.
We propose a viable model based on the $SU(3)_Ctimes SU(3)_Ltimes U(1)_X$ gauge group, augmented by the $U(1)_{L_g}$ global lepton number symmetry and the $Delta(27) times Z_3times Z_{16}$ discrete group, capable of explaining the Standard Model (SM) fermion masses and mixings, and having a low scale seesaw mechanism which can be tested at the LHC. In addition the model provides an explanation for the SM fermion masses and mixings. In the proposed model, small masses for the light active neutrinos are generated by an inverse seesaw mechanism caused by non renormalizable Yukawa operators and mediated by three very light Majorana neutrinos and the observed hierarchy of the SM fermion masses and mixing angles is produced by the spontaneous breaking of the $Delta(27) times Z_{3}times Z_{16}$ symmetry at very large energy scale. This neutrino mass generation mechanism is not presented in our previous 3-3-1 models with $Delta(27)$ group (Nucl.Phys. B913 (2016) 792-814 and Eur.Phys.J. C76 (2016) no.5, 242), where the masses of the light active neutrinos arise from a combination of type I and type II seesaw mechanisms (Nucl.Phys. B913 (2016) 792-814) as well as from a double seesaw mechanism (Eur.Phys.J. C76 (2016) no.5, 242). Thus, this work corresponds to the first implementation of the $Delta(27)$ symmetry in a 3-3-1 model with low scale seesaw mechanism.
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 on the Higgs vacuum expectation values (VEVs) in the Yukawa couplings, all of quarks have consistent masses, and a realistic quark mixing matrix can be realized at the first order of perturbation theory.
We construct a 3-3-1 model based on family symmetry S_4 responsible for the neutrino and quark masses. The tribimaximal neutrino mixing and the diagonal quark mixing have been obtained. The new lepton charge mathcal{L} related to the ordinary lepton charge L and a SU(3) charge by L=2/sqrt{3} T_8+mathcal{L} and the lepton parity P_l=(-)^L known as a residual symmetry of L have been introduced which provide insights in this kind of model. The expected vacuum alignments resulting in potential minimization can origin from appropriate violation terms of S_4 and mathcal{L}. The smallness of seesaw contributions can be explained from the existence of such terms too. If P_l is not broken by the vacuum values of the scalar fields, there is no mixing between the exotic and the ordinary quarks at the tree level.
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