scholarly journals A hybrid seesaw model and hierarchical neutrino flavor structures based on A4 symmetry

2021 ◽  
Author(s):  
Mayumi Aoki ◽  
Daiki Kaneko
Keyword(s):  
Dark Matter ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Hierarchical Structures ◽  
Double Beta Decay ◽  
Tree Level ◽  
Dark Matter Candidate ◽  
Flavor Symmetry ◽  
Seesaw Model ◽  
Majorana Phases

Abstract We propose a hybrid seesaw model based on A4 flavor symmetry, which generates a large hierarchical flavor structure. In our model, tree-level and one-loop seesaw mechanisms predict different flavor structures in the neutrino mass matrix, and generate a notable hierarchy among them. We find that such a hierarchical structure gives a large effective neutrino mass which can be accessible by next-generation neutrinoless double beta decay experiments. Majorana phases can also be predictable. The A4 flavor symmetry in the model is spontaneously broken to the Z2 symmetry, leading to a dark matter candidate which is assumed to be a neutral scalar field. The favored mass region of the dark matter is obtained by numerical computations of the relic abundance and the cross section of the nucleon. We also investigate the predictions of the several hierarchical flavor structures based on A4 symmetry for the effective neutrino mass and the Majorana phases, and find the characteristic features depending on the hierarchical structures.

scholarly journals NEUTRINO MASSES, LEPTON FLAVOR MIXING AND LEPTOGENESIS IN THE MINIMAL SEESAW MODEL

2007 ◽  
Vol 16 (01) ◽  
pp. 1-50 ◽  
Author(s):  
WAN-LEI GUO ◽  
ZHI-ZHONG XING ◽  
SHUN ZHOU
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Seesaw Model ◽  
Flavor Mixing ◽  
Majorana Neutrinos

We present a review of neutrino phenomenology in the minimal seesaw model (MSM), an economical and intriguing extension of the Standard Model with only two heavy right-handed Majorana neutrinos. Given current neutrino oscillation data, the MSM can predict the neutrino mass spectrum and constrain the effective masses of the tritium beta decay and the neutrinoless double-beta decay. We outline five distinct schemes to parameterize the neutrino Yukawa-coupling matrix of the MSM. The lepton flavor mixing and baryogenesis via leptogenesis are investigated in some detail by taking account of possible texture zeros of the Dirac neutrino mass matrix. We derive an upper bound on the CP-violating asymmetry in the decay of the lighter right-handed Majorana neutrino. The effects of the renormalization-group evolution on the neutrino mixing parameters are analyzed, and the correlation between the CP-violating phenomena at low and high energies is highlighted. We show that the observed matter-antimatter asymmetry of the Universe can naturally be interpreted through the resonant leptogenesis mechanism at the TeV scale. The lepton-flavor-violating rare decays, such as μ→e+γ, are also discussed in the supersymmetric extension of the MSM.

scholarly journals Super-Kamiokande neutrino oscillations and the supersymmetric model

2020 ◽  
Vol 9 ◽  
pp. 14
Author(s):  
A. Faessler
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Electron Neutrino ◽  
Tree Level ◽  
Supersymmetric Model ◽  
Neutrino Masses ◽  
Muon Neutrinos

The standard model predicts a ratio of 2 for the number of atmospheric muon to electron neutrinos, while super-Kamiokande and others measure a much smaller value (1.30±0.02 for super-Kamiokande). Super-Kamiokande is also able to measure roughly the direction and the energy of the neutrinos. The zenith-angle dependence for the muon neutrinos suggests that the muon neutrinos oscillate into a third neutrino species, either into the r neutrino or a sterile neutrino. This finding is inves- tigated within the supersymmetric model. The neutrinos mix with the neutralinos, this meaning the wino, the bino and the two higgsinos. The 7 x 7 mass matrix is calculated on the tree level. One finds that the mass matrix has three linearly dependent rows, which means that two masses are zero. They are identified with the two lightest neutrino masses. The fit of the super-Kamiokande data to oscillations between three neutrinos yields, together with the result of supersymmetry, that the third neutrino mass lies between 2x10^-2 and 10^-1 eV. The two lightest neutrino masses are in supersymmetry on the tree level zero. The averaged electron neutrino mass which is the essential parameter in the neutrinoless double-beta decay is given by {m_ve) ~ m_v3 P_ze < 0.8 x10^-2 eV (95% confidence limit). It is derived from the super-Kamiokande data in this supersymmetric model to be two orders smaller than the best value (1 eV) from the neutrinoless double-beta decay.

scholarly journals One-loop radiative seesaw dark matter and neutrinoless double beta decay with two zero flavor neutrino mass texture

2017 ◽  
Vol 32 (32) ◽  
pp. 1750186 ◽  
Author(s):  
Teruyuki Kitabayashi ◽  
Shinya Ohkawa ◽  
Masaki Yasuè
Keyword(s):  
Dark Matter ◽  
Beta Decay ◽  
Neutrino Mass ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Seesaw Model ◽  
Dark Matter Mass ◽  
The One ◽  
Analytical Expressions

We discuss the linkage between dark matter mass in the one-loop radiative seesaw model and the effective neutrino mass for the neutrinoless double beta decay. This linkage, which has been already numerically suggested, is confirmed to be a reasonable relationship by deriving analytical expressions for two zero flavor neutrino mass texture.

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 Electroweak corrections in a pseudo Nambu-Goldstone Dark Matter model revisited

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Seraina Glaus ◽  
Margarete Mühlleitner ◽  
Jonas Müller ◽  
Shruti Patel ◽  
Tizian Römer ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Parameter Space ◽  
Goldstone Boson ◽  
Indirect Evidence ◽  
Tree Level ◽  
Dark Matter Candidate ◽  
Nucleon Scattering ◽  
The Cross ◽  
Electroweak Corrections

Abstract Having so far only indirect evidence for the existence of Dark Matter a plethora of experiments aims at direct detection of Dark Matter through the scattering of Dark Matter particles off atomic nuclei. For the correct interpretation and identification of the underlying nature of the Dark Matter constituents higher-order corrections to the cross section of Dark Matter-nucleon scattering are important, in particular in models where the tree-level cross section is negligibly small. In this work we revisit the electroweak corrections to the dark matter-nucleon scattering cross section in a model with a pseudo Nambu-Goldstone boson as the Dark Matter candidate. Two calculations that already exist in the literature, apply different approaches resulting in different final results for the cross section in some regions of the parameter space leading us to redo the calculation and analyse the two approaches to clarify the situation. We furthermore update the experimental constraints and examine the regions of the parameter space where the cross section is above the neutrino floor but which can only be probed in the far future.

scholarly journals SUPERSYMMETRIC U(1) GAUGE REALIZATION OF THE DARK SCALAR DOUBLET MODEL OF RADIATIVE NEUTRINO MASS

2008 ◽  
Vol 23 (10) ◽  
pp. 721-725 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Neutrino Mass ◽  
Dark Matter Candidate ◽  
Neutrino Masses ◽  
Particle Interactions ◽  
The Standard Model ◽  
Doublet Model

Adding a second scalar doublet (η+, η0) and three neutral singlet fermions N1, 2, 3 to the Standard Model of particle interactions with a new Z2 symmetry, it has been shown that [Formula: see text] or [Formula: see text] is a good dark-matter candidate and seesaw neutrino masses are generated radiatively. A supersymmetric U(1) gauge extension of this new idea is proposed, which enforces the usual R-parity of the Minimal Supersymmetric Standard Model, and allows this new Z2 symmetry to emerge as a discrete remnant.

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