scholarly journals Hidden relations in three generation seesaw model with Dirac mass matrix of four-zero texture

2019 ◽  
Vol 799 ◽  
pp. 135046
Author(s):  
Takuya Morozumi ◽  
Yusuke Shimizu ◽  
Hiroyuki Umeeda ◽  
Akihiro Yuu
Keyword(s):  
Mass Matrix ◽  
Dirac Mass ◽  
Seesaw Model

BIPAIR NEUTRINO MIXING AND LEPTOGENESIS

2013 ◽  
Vol 28 (07) ◽  
pp. 1350016 ◽  
Author(s):  
TERUYUKI KITABAYASHI
Keyword(s):  
Mass Matrix ◽  
Baryon Number ◽  
Neutrino Mixing ◽  
Lepton Asymmetry ◽  
Mixing Angle ◽  
Dirac Mass ◽  
Seesaw Model ◽  
Reactor Neutrino ◽  
The Universe

We estimate the baryon–photon ratio in the Universe via the leptogenesis scenario in the framework of the minimal seesaw model with a minimally modified bipair neutrino mixing. We assume that one of the elements of the 3 × 2 Dirac mass matrix mD is exactly zero. It turns out that the lepton asymmetry as well as baryon number of the Universe definitely depends on the reactor neutrino mixing angle in the cases of (mD)11 = 0 and (mD)12 = 0. The allowed region of the Majorana CP phase is separated into three regions related to the assumption of either (mD)11 = 0, (mD)21, 31 = 0 or (mD)12 = 0.

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 SEESAW AND LEPTOGENESIS: A TRIANGULAR ANSATZ

2011 ◽  
Vol 26 (18) ◽  
pp. 1375-1379 ◽  
Author(s):  
D. FALCONE
Keyword(s):  
Charged Lepton ◽  
Mass Matrix ◽  
Triangular Matrix ◽  
Unitary Matrix ◽  
Seesaw Mechanism ◽  
Dirac Mass ◽  
Majorana Mass ◽  
Dirac Matrix

A triangular ansatz for the seesaw mechanism and baryogenesis via leptogenesis is explored. In a basis where both the charged lepton and the Majorana mass matrix are diagonal, the Dirac mass matrix can generally be written as the product of a unitary times a triangular matrix. We assume the unitary matrix to be the identity and then an upper triangular Dirac matrix. Constraints from bilarge lepton mixing and leptogenesis are studied.

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 The smallest neutrino mass revisited

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Shun Zhou
Keyword(s):  
Renormalization Group ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Operator ◽  
Matching Condition ◽  
Effective Dimension ◽  
Seesaw Model ◽  
Supersymmetric Version ◽  
Renormalization Group Equations ◽  
The One

Abstract As is well known, the smallest neutrino mass turns out to be vanishing in the minimal seesaw model, since the effective neutrino mass matrix Mν is of rank two due to the fact that only two heavy right-handed neutrinos are introduced. In this paper, we point out that the one-loop matching condition for the effective dimension-five neutrino mass operator can make an important contribution to the smallest neutrino mass. By using the available one-loop matching condition and two-loop renormalization group equations in the supersymmetric version of the minimal seesaw model, we explicitly calculate the smallest neutrino mass in the case of normal neutrino mass ordering and find m1 ∈ [10−8, 10−10] eV at the Fermi scale ΛF = 91.2 GeV, where the range of m1 results from the uncertainties on the choice of the seesaw scale ΛSS and on the input values of relevant parameters at ΛSS.

scholarly journals Linear seesaw model with a modular $S_4$ flavor symmetry

2022 ◽  
Author(s):  
Takaaki Nomura ◽  
Hiroshi Okada
Keyword(s):  
Neutrino Mass ◽  
High Energy Physics ◽  
Mass Matrix ◽  
High Energy ◽  
Mass Hierarchy ◽  
Creative Commons ◽  
Seesaw Model ◽  
Modern Physics ◽  
Normal Mass ◽  
Academy Of Sciences

Abstract We discuss a linear seesaw model with as minimum field content as possible, introducing a modular $S_4$ with the help of gauged $U(1)_{B-L}$ symmetries. Due to rank two neutrino mass matrix, we have a vanishing neutrino mass eigenvalue, and only the normal mass hierarchy of neutrinos is favored through the modular $S_4$ symmetry.In our numerical $\Delta \chi^2$ analysis, we especially find rather sharp prediction on sum of neutrino masses to be around $60$ meV in addition to the other predictions. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

scholarly journals THE MINIMAL TYPE-II SEESAW MODEL AND FLAVOR-DEPENDENT LEPTOGENESIS

2008 ◽  
Vol 23 (21) ◽  
pp. 3412-3415
Author(s):  
SHU LUO ◽  
ZHI-ZHONG XING
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Baryon Number ◽  
Majorana Neutrino ◽  
Type Ii ◽  
Neutrino Mixing ◽  
Seesaw Model ◽  
Mixing Matrix ◽  
Current Experimental Data ◽  
Minimal Type

Current experimental data allow the zero value for one neutrino mass, either m1 = 0 or m3 = 0. This observation implies that a realistic neutrino mass texture can be established by starting from the limit (a) m1 = m2 = 0 and m3 ≠ 0 or (b) m1 = m2 ≠ 0 and m3 = 0. In both cases, we may introduce a particular perturbation which ensures the resultant neutrino mixing matrix to be the tri-bimaximal mixing pattern or its viable variations. We find that it is natural to incorporate this kind of neutrino mass matrix in the minimal Type-II seesaw model with only one heavy right-handed Majorana neutrino N. We show that it is possible to account for the cosmological baryon number asymmetry in the m3 = 0 case via thermal leptogenesis, in which the CP-violating asymmetry of N decays is attributed to the electron flavor.

scholarly journals Renormalization group evolution induced leptogenesis in the minimal seesaw model with the trimaximal mixing and mu-tau reflection symmetry

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Zhen-hua Zhao
Keyword(s):  
Renormalization Group ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Baryon Asymmetry ◽  
Neutrino Mass Matrix ◽  
Reflection Symmetry ◽  
Normal Case ◽  
Seesaw Model ◽  
Group Evolution ◽  
Evolution Effect

Abstract In this paper, we consider the imbedding of the popular and well-motivated trimaximal mixing and μ–τ reflection symmetry (which can help us shape the forms of the neutrino mass matrix) in the minimal seesaw model (which contains much fewer parameters than the general seesaw model) with two TeV-scale right-handed neutrinos (for realizing a low-scale seesaw) of nearly degenerate masses (for realizing a resonant leptogenesis). However, either for the trimaximal mixing scenario (which is realized through the Form Dominance approach here) or for the μ–τ reflection symmetry scenario, leptogenesis cannot proceed. To address this issue, we consider the possibility that the special forms of the neutrino mass matrix for the trimaximal mixing and μ–τ reflection symmetry are slightly broken by the renormalization group evolution effect, thus allowing leptogenesis to proceed. It is found that in the normal case of the neutrino mass ordering, the baryon asymmetry thus generated can reproduce the observed value. For completeness, we have also extended our analysis to the scenario that two right-handed neutrinos are not nearly degenerate any more. Unfortunately, in this scenario the final baryon asymmetry is smaller than the observed value by several orders of magnitude.

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