scholarly journals Scalar clockwork and flavor neutrino mass matrix

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Teruyuki Kitabayashi
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Model Parameters ◽  
Yukawa Couplings ◽  
Flavor Structure ◽  
Site Number ◽  
The Standard Model

Abstract We study the capability of generating the correct flavor neutrino mass matrix in a scalar clockwork model. First, we assume that the flavor structure is controlled by the Yukawa couplings as in the standard model. In this case, the correct flavor neutrino mass matrix could be obtained by appropriate Yukawa couplings $Y_{\ell^\prime\ell}$ where $\ell^\prime, \ell = e, \mu, \tau$. Next, we assume that the Yukawa couplings are extremely democratic: $|Y_{\ell^\prime\ell} |=1$. In this case, the model parameters of the scalar clockwork sector, such as the site number of a clockwork gear in a clockwork chain, should have the flavor indices $\ell^\prime$ and/or $\ell$ to generate the correct flavor neutrino mass matrix. We show some examples of assignments of the flavor indices which can yield the correct flavor neutrino mass matrix.

scholarly journals HIDING THE EXISTENCE OF A FAMILY SYMMETRY IN THE STANDARD MODEL

2005 ◽  
Vol 20 (36) ◽  
pp. 2767-2774 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Higgs Sector ◽  
Higgs Doublet ◽  
Neutrino Mass Matrix ◽  
Tree Level ◽  
Family Symmetry ◽  
The Standard Model

If a family symmetry exists for the quarks and leptons, the Higgs sector is expected to be enlarged to be able to support the transformation properties of this symmetry. There are, however, three possible generic ways (at tree level) of hiding this symmetry in the context of the Standard Model with just one Higgs doublet. All three mechanisms have their natural realizations in the unification symmetry E6 and one in SO (10). An interesting example based on SO (10)×A4 for the neutrino mass matrix is discussed.

scholarly journals LEPTON FAMILY SYMMETRY AND NEUTRINO MASS MATRIX

2004 ◽  
Vol 19 (08) ◽  
pp. 577-582 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Solar Neutrino ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Diagonal Form ◽  
Family Symmetry ◽  
The Standard Model ◽  
Lepton Family

The standard model of leptons is extended to accommodate a discrete Z3×Z2 family symmetry. After rotating the charged-lepton mass matrix to its diagonal form, the neutrino mass matrix reveals itself as very suitable for explaining atmospheric and solar neutrino oscillation data. A generic requirement of this approach is the appearance of three Higgs doublets at the electroweak scale, with observable flavor violating decays.

scholarly journals A radiatively induced neutrino mass model with hidden local U(1) and LFV processes ℓi → ℓjγ, μ → eZ′ and μe → ee

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Takaaki Nomura ◽  
Hiroshi Okada ◽  
Yuichi Uesaka
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Mass Model ◽  
Mass Generation ◽  
Hidden Sector ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Neutrino Mass Generation

Abstract We investigate a model based on hidden U(1)X gauge symmetry in which neutrino mass is induced at one-loop level by effects of interactions among particles in hidden sector and the Standard Model leptons. Neutrino mass generation is also associated with U(1)X breaking scale which is taken to be low to suppress neutrino mass. Then we formulate neutrino mass matrix, lepton flavor violating processes and muon g − 2 which are induced via interactions among Standard Model leptons and particles in U(1)X hidden sector that can be sizable in our scenario. Carrying our numerical analysis, we show expected ratios for these processes when generated neutrino mass matrix can fit the neutrino data.

scholarly journals Neutrino mass matrix in a gauge group SU(2)L × U(1)e × U(1)μ × U(1)τ

2019 ◽  
Vol 34 (12) ◽  
pp. 1950066
Author(s):  
Fayyazuddin
Keyword(s):  
Gauge Group ◽  
Neutrino Mass ◽  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Neutrino Mass Matrix ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
The Right ◽  
Higgs Scalar

The electroweak unification group [Formula: see text] in which each fermion multiplet has its own [Formula: see text] factor was proposed in 1986 to get the neutrino mass matrix. In this paper, the gauge group [Formula: see text] is restricted to lepton section only, leaving quark multiplets as in the Standard Model. In addition to lepton multiplets [Formula: see text], [Formula: see text] and [Formula: see text], there are three [Formula: see text] singlet right-handed neutrinos [Formula: see text]’s. With the breaking of [Formula: see text] to [Formula: see text], the right-handed neutrinos acquire heavy Majorana masses. Three heavy right-handed neutrinos [Formula: see text]’s are available to generate a [Formula: see text] nondiagonal neutrino mass matrix in terms of three Yukawa couplings [Formula: see text], [Formula: see text], [Formula: see text] of the Higgs scalar doublet to [Formula: see text], [Formula: see text], [Formula: see text] with [Formula: see text], [Formula: see text] and [Formula: see text], respectively. Three Yukawa couplings can be arranged and expressed in terms of masses [Formula: see text], [Formula: see text], [Formula: see text] in three different ways to obtain the results of interest for Case 1: [Formula: see text]; Case 2: [Formula: see text]; Case 3: [Formula: see text]. The results obtained for the three cases are compared with the experimental data from neutrino oscillations. Cases 1 and 2 are relevant for solar neutrino oscillations whereas Case 3 is relevant for atmospheric neutrino oscillations.

scholarly journals Type II seesaw origin of nonzero θ13, δCP and leptogenesis

2014 ◽  
Vol 29 (22) ◽  
pp. 1450108 ◽  
Author(s):  
Debasish Borah
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Type I ◽  
Type Ii ◽  
Mixing Angle ◽  
Yukawa Couplings ◽  
Minimal Structure ◽  
Reactor Mixing ◽  
The Universe

We discuss the possible origin of nonzero reactor mixing angle θ13 and Dirac CP phase δ CP in the leptonic sector from a combination of type I and type II seesaw mechanisms. Type I seesaw contribution to neutrino mass matrix is of tri-bimaximal (TBM) type which gives rise to vanishing θ13 leaving the Dirac CP phase undetermined. If the Dirac neutrino mass matrix is assumed to take the diagonal charged lepton (CL) type structure, such a TBM type neutrino mass matrix originating from type I seesaw corresponds to real values of Dirac Yukawa couplings in the terms [Formula: see text]. This makes the process of right-handed heavy neutrino decay into a light neutrino and Higgs (N → νH) CP preserving ruling out the possibility of leptogenesis. Here we consider the type II seesaw term as the common origin of nonzero θ13 and δ CP by taking it as a perturbation to the leading order TBM type neutrino mass matrix. First, we numerically fit the type I seesaw term by taking oscillation as well as cosmology data and then compute the predictions for neutrino parameters after the type II seesaw term is introduced. We consider a minimal structure of the type II seesaw term and check whether the predictions for neutrino parameters lie in the 3σ range. We also compute the predictions for baryon asymmetry of the universe by considering type II seesaw term as the only source of CP violation and compare it with the latest cosmology data.

scholarly journals EXTENDING THE STANDARD MODEL: AN UPPER BOUND FOR A NEUTRINO MASS FROM THE RARE DECAY $K^+\rightarrow\pi^+\nu\bar\nu$

2000 ◽  
Vol 15 (08) ◽  
pp. 579-586 ◽  
Author(s):  
B. MACHET
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Upper Bound ◽  
Average Rate ◽  
Rare Decay ◽  
Yukawa Couplings ◽  
Flavor Changing ◽  
Upper Limit ◽  
Quartic Term ◽  
The Standard Model

The standard model seeming at a loss to account for the present experimental average rate for the rare decay [Formula: see text], we tackle the question with the extension of the Glashow–Salam–Weinberg model to an SU (2)L× U (1) gauge theory of J = 0 mesons proposed in Ref. 7, in which, in addition, the neutrinos are given Dirac masses from Yukawa couplings to the Higgs boson. The latter triggers a new contribution to this decay through flavor changing neutral currents that arise in the quartic term of the symmetry breaking potential; it becomes sizable for a neutrino mass in the MeV range; the experimental upper limit for the decay rate translates into an upper bound of 5.5 MeV for the mass of the neutrino, three times lower than the present direct bounds.

scholarly journals NEUTRINO MAGNETIC MOMENTS AND MINIMAL SUPERSYMMETRIC SO(10) MODEL

2004 ◽  
Vol 19 (28) ◽  
pp. 4825-4833 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
TATSURU KIKUCHI ◽  
NOBUCHIKA OKADA
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Magnetic Moments ◽  
Matrix Elements ◽  
Mass Matrices ◽  
The Standard Model ◽  
Order Of Magnitude ◽  
Majorana Neutrinos ◽  
Soft Supersymmetry Breaking

We examine supersymmetric contributions to transition magnetic moments of Majorana neutrinos. We first give the general formula for it. In concrete evaluations, informations of neutrino mass matrix elements including CP phases are necessary. Using unambiguously determined neutrino mass matrices in recently proposed minimal supersymmetric SO (10) model, the transition magnetic moments are calculated. The resultant neutrino magnetic moments with the input soft supersymmetry breaking masses being of order 1 TeV are found to be roughly an order of magnitude larger than those calculated in the standard model extended to incorporate the see-saw mechanism.

scholarly journals NEUTRINO PHYSICS: OPEN THEORETICAL QUESTIONS

2004 ◽  
Vol 19 (08) ◽  
pp. 1180-1197 ◽  
Author(s):  
A. Y. SMIRNOV
Keyword(s):  
Neutrino Physics ◽  
Standard Model ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
New Physics ◽  
Present Knowledge ◽  
Beyond The Standard Model ◽  
Neutrino Mass And Mixing ◽  
Open Questions ◽  
The Standard Model

We know that neutrino mass and mixing provide a window to physics beyond the Standard Model. Now this window is open, at least partly. And the questions are: what do we see, which kind of new physics, and how far "beyond"? I summarize the present knowledge of neutrino mass and mixing, and then formulate the main open questions. Following the bottom-up approach, properties of the neutrino mass matrix are considered. Then different possible ways to uncover the underlying physics are discussed. Some results along the line of seesaw, GUT and SUSY GUT are reviewed.

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