scholarly journals GAUGE BOSON FAMILIES IN GRAND UNIFIED THEORIES OF FERMION MASSES: $E_6^4 \rtimes S_4$

2007 ◽  
Vol 22 (14n15) ◽  
pp. 2469-2491 ◽  
Author(s):  
FRANCESCO CARAVAGLIOS ◽  
STEFANO MORISI
Keyword(s):  
Gauge Group ◽  
Gauge Boson ◽  
Neutrino Masses ◽  
Group Factor ◽  
Second Quantization ◽  
Gauge Bosons ◽  
Fermion Masses ◽  
The Standard Model ◽  
Electron Field ◽  
Neutrino Masses And Mixings

In third quantization the origin of fermion families is easy to understand: the electron field, the muon field and the tau field are identical fields in precisely the same sense as three electrons are identical and indistinguishable particles of a theory of second quantization. In both cases, the permutation of these fields or particles leaves the Lagrangian invariant. One can also extend the concept of family to gauge bosons. This can be obtained through the semidirect product of the gauge group with the group of permutations of n objects. In this paper we have studied the group [Formula: see text]. We explain why we have chosen E6 as fundamental gauge group factor and why we start with a model with four gauge boson/fermion families to accommodate and to fit the Standard Model with only three fermion families. We suggest a possible symmetry breaking pattern of [Formula: see text] that could explain quark, lepton and neutrino masses and mixings.

scholarly journals THE PROBLEM OF NEUTRINO MASSES IN EXTENSIONS OF THE STANDARD MODEL

2001 ◽  
Vol 16 (32) ◽  
pp. 5101-5199 ◽  
Author(s):  
ISABELLA MASINA
Keyword(s):  
Proton Decay ◽  
Fine Tuning ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Mixing Angle ◽  
Grand Unified Theories ◽  
Triplet Splitting ◽  
Fermion Masses ◽  
The Standard Model ◽  
Neutrino Masses And Mixings

We review the problem of neutrino masses and mixings in the context of grand unified theories. After a brief summary of the present experimental status of neutrino physics, we describe how the see-saw mechanism can automatically account for the large atmospheric mixing angle. We provide two specific examples where this possibility is realized by means of a flavor symmetry. We then review in some detail the various severe problems which plague minimal GUT models (like the doublet–triplet splitting and proton-decay) and which force us to investigate the possibility of constructing more elaborate but realistic models. We then show an example of a quasirealistic SUSY SU(5) model which, by exploiting the crucial presence of an Abelian flavor symmetry, does not require any fine-tuning and predicts a satisfactory phenomenology with respect to coupling unification, fermion masses and mixings and bounds from proton decay.

scholarly journals A NewS4Flavor Symmetry in 3-3-1 Model with Neutral Fermions

2014 ◽  
Vol 2014 ◽  
pp. 1-24 ◽  
Author(s):  
V. V. Vien ◽  
H. N. Long
Keyword(s):  
Scalar Potential ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Gauge Bosons ◽  
Quark Masses ◽  
Model Based ◽  
Fermion Masses ◽  
The Standard Model ◽  
Mixing Matrix ◽  
The Difference

A newS4flavor model based onSU(3)C⊗SU(3)L⊗U(1)Xgauge symmetry responsible for fermion masses and mixings is constructed. The neutrinos get small masses from only an antisextet ofSU(3)Lwhich is in a doublet underS4. In this work, we assume the VEVs of the antisextet differ from each other underS4and the difference of these VEVs is regarded as a small perturbation, and then the model can fit the experimental data on neutrino masses and mixings. Our results show that the neutrino masses are naturally small and a deviation from the tribimaximal neutrino mixing form can be realized. The quark masses and mixing matrix are also discussed. The number of required Higgs multiplets is less and the scalar potential of the model is simpler than those of the model based onS3and our previousS4model. The assignation of VEVs to antisextet 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 bosons is considered.

scholarly journals THE D4FLAVOR SYMMETRY IN 3-3-1 MODEL WITH NEUTRAL LEPTONS

2013 ◽  
Vol 28 (32) ◽  
pp. 1350159 ◽  
Author(s):  
V. V. VIEN ◽  
H. N. LONG
Keyword(s):  
Scalar Potential ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Gauge Bosons ◽  
Ckm Matrix ◽  
Quark Masses ◽  
Model Based ◽  
Fermion Masses ◽  
The Standard Model ◽  
Mixing Matrix

We construct a D4flavor model based on SU(3)C⊗SU(3)L⊗U(1)Xgauge symmetry responsible for fermion masses and mixings. The neutrinos get small masses from antisextets which are in a singlet and a doublet under D4. If the D4symmetry is violated as perturbation by a Higgs triplet under SU(3)Land lying in [Formula: see text] of D4, 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 S3and S4. 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.

GAUGE BOSON MASSES FROM FERMION MASSES?

1992 ◽  
Vol 07 (22) ◽  
pp. 1991-1996 ◽  
Author(s):  
R. FOOT ◽  
S. TITARD
Keyword(s):  
Gauge Boson ◽  
Z Boson ◽  
Heavy Fermions ◽  
Mass Matrix ◽  
Gauge Bosons ◽  
Fermion Masses ◽  
The Masses

We examine the possibility that the masses of the W and Z gauge bosons are induced radiatively from the masses of heavy fermions. From experiment we know that [Formula: see text][Formula: see text]. We point out that this relation can be naturally obtained if the W and Z boson masses are radiatively generated from heavy fermions which arise from a mass matrix which has large electroweak violating masses as well as very large electroweak invariant masses. Two examples of this are considered: The usual see-saw neutrino model and the SU(5)c/quark-lepton symmetric models.

TeV Scale B – L Phenomenology at LHC

2007 ◽  
Vol 22 (31) ◽  
pp. 5889-5908 ◽  
Author(s):  
M. Abbas ◽  
W. Emam ◽  
S. Khalil ◽  
M. Shalaby
Keyword(s):  
Standard Model ◽  
Gauge Boson ◽  
Cross Sections ◽  
Branching Ratios ◽  
Higgs Production ◽  
Neutrino Masses ◽  
Natural Explanation ◽  
The Standard Model ◽  
The Cross

We present the phenomenology of the low scale U(1)B–L extension of the standard model and its implications at LHC. We show that this model provides a natural explanation for the presence of three right-handed neutrinos and can naturally account the observed neutrino masses and mixing. We study the decay and production of the extra gauge boson and the SM singlet scalar (heavy Higgs) predicted in this type of models. We find that the cross sections of the SM-like Higgs production are reduced by ~ 20% – 30%, while its decay branching ratios remain intact. The extra Higgs has relatively small cross sections and the branching ratios of Z′ → l+l− are of order ~ 20% compared to ~ 3% of the SM results.

scholarly journals Baryogenesis and dark matter in U(1) extensions

2017 ◽  
Vol 32 (15) ◽  
pp. 1740005 ◽  
Author(s):  
Wan-Zhe Feng ◽  
Pran Nath
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Lepton Number ◽  
Current Data ◽  
Neutrino Masses ◽  
Neutrino Experiment ◽  
The Standard Model ◽  
Reactor Neutrino ◽  
The Universe ◽  
Neutrino Masses And Mixings

A brief review is given of some recent works where baryogenesis and dark matter have a common origin within the U(1) extensions of the Standard Model (SM) and of the minimal supersymmetric Standard Model (MSSM). The models considered generate the desired baryon asymmetry and the dark matter to baryon ratio. In one model, all of the fundamental interactions do not violate lepton number, and the total [Formula: see text] in the Universe vanishes. In addition, one may also generate a normal hierarchy of neutrino masses and mixings in conformity with the current data. Specifically, one can accommodate [Formula: see text] consistent with the data from Daya Bay reactor neutrino experiment.

scholarly journals MUONIUM–ANTIMUONIUM OSCILLATIONS AND MASSIVE MAJORANA NEUTRINOS

2004 ◽  
Vol 19 (04) ◽  
pp. 297-306 ◽  
Author(s):  
T. E. CLARK ◽  
S. T. LOVE
Keyword(s):  
Matrix Element ◽  
Interesting Case ◽  
Neutrino Masses ◽  
Leading Order ◽  
Seesaw Mechanism ◽  
The Standard Model ◽  
Oscillation Process ◽  
Majorana Neutrinos ◽  
Order Matrix Element ◽  
Neutrino Masses And Mixings

The electron and muon number violating muonium–antimuonium oscillation process can proceed provided that neutrinos have nonzero masses and mix among the various generations. Modifying the Standard Model only by the inclusion of singlet right-handed neutrino fields and allowing for general neutrino masses and mixings, the leading order matrix element contributing to this process is computed. For the particularly interesting case where the neutrino masses are generated by a seesaw mechanism with a very large Majorana mass MR≫MW, it is found that both the very light and very heavy Majorana neutrinos each give comparable contributions to the oscillation time scale proportional to [Formula: see text]. Present experimental limits set by the non-observation of the oscillation process sets a lower limit on MR of roughly of order 104 GeV.

scholarly journals SYSTEMATIC STUDY OF THESU(3)c⊗SU(4)L⊗U(1)XGAUGE SYMMETRY

2007 ◽  
Vol 22 (06) ◽  
pp. 435-447 ◽  
Author(s):  
WILLIAM A. PONCE ◽  
LUIS A. SÁNCHEZ
Keyword(s):  
Standard Model ◽  
Gauge Group ◽  
Gauge Boson ◽  
Systematic Study ◽  
Infinite Number ◽  
Model Based ◽  
First Case ◽  
The Standard Model ◽  
Family Models

We carry out a systematic study of possible extensions of the standard model based on the gauge group SU (3)c⊗ SU (4)L⊗ U (1)X. We consider models with particles having exotic electric charges and also models which do not contain exotic electric charges in the gauge boson sector or in the fermion sector. For the first case an infinite number of models can, in principle, be constructed, while the restriction to non-exotic electric charges only allows for eight different anomaly-free models. Four of them are three-family models in the sense that anomalies cancel by an interplay between the three families, and another two are one-family models where anomalies cancel family by family as in the standard model. The remaining two are two-family models.

scholarly journals SUPERSTRING MODELS CHALLENGED BY RARE PROCESSES

1987 ◽  
Vol 02 (03) ◽  
pp. 831-890 ◽  
Author(s):  
B. A. CAMPBELL ◽  
J. ELLIS ◽  
K. ENQVIST ◽  
M. K. GAILLARD ◽  
D. V. NANOPOULOS
Keyword(s):  
Upper Bounds ◽  
Low Energy ◽  
Neutrino Masses ◽  
Dynamical Models ◽  
Gauge Bosons ◽  
Yukawa Couplings ◽  
Flavor Changing ◽  
The Standard Model ◽  
New Interactions ◽  
Matter Fields

Superstring models compactified on Calabi–Yau manifolds contain additional matter fields and gauge bosons beyond those in the Standard Model. The new matter and gauge couplings would make additional contributions to conventional electroweak processes, generate extra flavor-changing neutral interactions, and mediate new interactions leading to proton decay and neutrino masses. We use the phenomenological constraints on such effects to derive upper bounds on Yukawa couplings in low-energy dynamical models inspired by the superstring. We draw attention to the processes which give the best bounds on new Yukawa couplings, and which are those where novel superstring effects might first appear as experimental sensitivity is improved. Our bounds are not sufficient to exclude most superstring models with additional light particles, but do suggest that some couplings are too small to realize certain scenarios for symmetry breaking by radiative corrections.

scholarly journals Rare decays of the top quark mediated by Z′ gauge bosons and flavor violation

2020 ◽  
Vol 35 (18) ◽  
pp. 2050153
Author(s):  
J. I. Aranda ◽  
D. Espinosa-Gómez ◽  
J. Montaño ◽  
F. Ramírez-Zavaleta ◽  
E. S. Tututi
Keyword(s):  
Gauge Boson ◽  
Top Quark ◽  
Branching Ratios ◽  
Gauge Bosons ◽  
Flavor Violation ◽  
Gauge Symmetries ◽  
Quark Decays ◽  
The Standard Model ◽  
Order Of Magnitude ◽  
The One

The rare top quark decays mediated by a new neutral massive gauge boson that is predicted in models with extended gauge symmetries are studied. We focus on the processes [Formula: see text] induced at the one loop level, where [Formula: see text], by considering different extended models. It is found that, within a broad range of mass of the new neutral gauge boson, the models predict branching ratios for the decays in study that are competitive with respect to the corresponding branching ratios in the Standard Model (SM). In order to establish bound on our branching ratios, we consider the recent experimental bounds as [Formula: see text], depending on the model, which also impose restrictions on our calculation. Even in this case, the resulting branching ratios are of the same order of magnitude as that predicted by the SM. It should be noted that for the case of two models studied here, since no experimental bound exists to compare with, the results could be important, as they are, in the best of cases, two orders of magnitude larger than the predicted by the SM.

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