scholarly journals CONSERVING THE LEPTON NUMBER Le-Lμ-LτIN THE EXACT SOLUTION OF A 3-3-1 GAUGE MODEL WITH RIGHT-HANDED NEUTRINOS

2007 ◽  
Vol 22 (13) ◽  
pp. 939-948 ◽  
Author(s):  
ADRIAN PALCU
Keyword(s):  
Exact Solution ◽  
Mass Matrix ◽  
Mass Splitting ◽  
Lepton Number ◽  
Mass Hierarchy ◽  
Gauge Model ◽  
Mixing Angles ◽  
Neutrino Sector ◽  
Absolute Mass ◽  
Breaking Scale

In this paper we consider a plausible scenario with conserved lepton number L = Le-Lμ-Lτwithin the framework of the exact solution of a particular 3-3-1 gauge model. We discuss the consequences of conserving this global leptonic symmetry from the viewpoint of the neutrino mass matrix constructed via special Yukawa terms (involving tensor products among Higgs triplets). We prove that the actual experimental data can naturally be reproduced by our scenario since soft breaking terms with respect to this lepton symmetry are properly introduced. As a consequence, our solution predicts for the neutrino sector the correct mass splitting ratio [Formula: see text], the inverted mass hierarchy, the correct values for the observed mixing angles ( sin2θ23≃0.5 and sin2θ12= 0.31) and the absolute mass of the lightest neutrino (m0~ 0.001 eV) independent of the breaking scale of the model.

scholarly journals NEUTRINO MASS SQUARED DIFFERENCES IN THE EXACT SOLUTION OF A 3-3-1 GAUGE MODEL WITHOUT EXOTIC ELECTRIC CHARGES

2006 ◽  
Vol 21 (27) ◽  
pp. 2027-2041 ◽  
Author(s):  
ADRIAN PALCU
Keyword(s):  
Exact Solution ◽  
Neutrino Mass ◽  
Mass Splitting ◽  
Mass Hierarchy ◽  
Gauge Model ◽  
Neutrino Sector ◽  
Absolute Mass ◽  
The Standard Model ◽  
Majorana Neutrinos ◽  
Suitable Approximation

The mass splittings for the Majorana neutrinos in the exact solution of a particular 3-3-1 gauge model are computed in detail. Since both sin2θ13≃0 and the mass splitting ratio rΔ≃0.033 are taken into account as phenomenological evidence, the analytical calculations in the leading order seem to predict an inverted mass hierarchy and a matrix with a texture based on a very close approximation to the bi-maximal mixing. The resulting formulas for the mass squared differences can naturally accommodate the available data if the unique free parameter a of the model gets very small values ~ 10-15. Consequently, the smallness of the parameter requires (according to our method) a large breaking scale 〈ϕ〉 ~ 106–107TeV. Hence, the results concerning the neutrino mass splittings lead to a more precise tuning in the exact solution of the 3-3-1 model and enable it — at the same time — to recover all the Standard Model phenomenology and predict the mass spectrum of the new gauge bosons Z′, X, Y in accordance with the actual data. The minimal absolute mass in the neutrino sector is also obtained, m0≃0.0035 eV, in the case of our suitable approximation for the bi-maximal mixing.

scholarly journals THE EXACT EIGENSTATES OF THE NEUTRINO MASS MATRIX WITHOUT CP-PHASE VIOLATION

2007 ◽  
Vol 22 (20) ◽  
pp. 1459-1467 ◽  
Author(s):  
ADRIAN PALCU
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Lepton Number ◽  
Neutrino Mass Matrix ◽  
Exact Mass ◽  
Mixing Angles ◽  
Mass Eigenstates ◽  
Neutrino Sector ◽  
Absolute Mass ◽  
Analytical Expressions

In this paper we obtain the exact mass-eigenstates of the Majorana physical neutrinos. We start by taking into account a general 3 × 3 mass matrix (ignoring any CP-phase violation). It is then diagonalized by exactly solving an appropriate set of equations. The solution provides straightforwardly the mass eigenvalues depending on the diagonal entries and mixing angles. Finally, the consequences of these analytical expressions are discussed assuming certain restrictions such as the global lepton number L = Le- Lμ- Lτ(rigorously conserved or softly broken) and the μ - τ interchange symmetry. The minimal absolute mass in the neutrino sector is also obtained since the two plausible scenarios invoked above are employed.

scholarly journals On Yukawa Couplings in the Zee-Babu Model

2013 ◽  
Vol 23 (3) ◽  
pp. 193
Author(s):  
Hoang Ngoc Long ◽  
Vo Van Vien
Keyword(s):  
Exact Solution ◽  
Cp Violation ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Mass Hierarchy ◽  
Yukawa Couplings ◽  
Neutrino Sector ◽  
Normal Mass

The exact solution for neutrino mass matrix of the Zee-Babu modelis derived. The tribimaximal mixing imposes  the conditions on the Yukawa couplings, from  which the normal mass hierarchy ispreferred. The derived conditions give a possibility of maximal \(CP\) violation in the neutrino sector.

scholarly journals Neutrino mixing with nonzero θ13 in Zee–Babu model

2014 ◽  
Vol 29 (13) ◽  
pp. 1450072 ◽  
Author(s):  
Hoang Ngoc Long ◽  
Vo Van Vien
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Recent Experimental Data ◽  
Mass Hierarchy ◽  
Neutrino Mixing ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angles ◽  
Yukawa Couplings ◽  
Neutrino Sector ◽  
Normal Mass

The exact solution for the neutrino mass matrix of the Zee–Babu model is derived. Tribimaximal mixing imposes conditions on the Yukawa couplings, from which the normal mass hierarchy is preferred. The derived conditions give a possibility of Majorana maximal CP violation in the neutrino sector. We have shown that nonzero θ13 is generated if Yukawa couplings between leptons almost equal to each other. The model gives some regions of the parameters where neutrino mixing angles and the normal neutrino mass hierarchy obtained are consistent with the recent experimental data.

NEUTRINO MASSES AND TeV SCALE RESONANT LEPTOGENESIS FROM SUPERSYMMETRY BREAKING

2006 ◽  
Vol 21 (21) ◽  
pp. 1629-1646 ◽  
Author(s):  
STEPHEN M. WEST
Keyword(s):  
Supersymmetry Breaking ◽  
Mass Matrix ◽  
Mass Splitting ◽  
Light Neutrino ◽  
Tree Level ◽  
Neutrino Masses ◽  
Yukawa Couplings ◽  
Neutrino Sector ◽  
The One ◽  
The Right

We review a class of supersymmetric models in which the light neutrino masses result from higher-dimensional supersymmetry-breaking terms in the MSSM super- and Kähler-potentials. The mechanism used in these models is closely related to the Giudice–Masiero mechanism for the MSSM μ parameter and leads to TeV-scale right-handed neutrino and sneutrino states. In these models, the dominant contribution to the light neutrino (Majorana) mass matrix is a one-loop term with a sub-dominant tree-level "seesaw" contribution. It is also shown that it is possible to construct a natural model of TeV-scale leptogenesis via the resonant behavior of the one-loop self-energy contribution to the right-handed neutrino (Ni) decay. This model addresses the primary problems of previous phenomenological studies of low-energy leptogenesis: a rational for TeV-scale right-handed neutrinos with small Yukawa couplings; the origin of the tiny, but non-zero mass splitting required between at least two Ni masses; and the necessary non-trivial breaking of flavor symmetries in the right-handed neutrino sector.

scholarly journals Relating lepton mixing angles with lepton mass hierarchy

2016 ◽  
Vol 31 (04n05) ◽  
pp. 1650002
Author(s):  
Debasish Borah
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Mass Matrices ◽  
Model Independent ◽  
The Difference

We revisit the possibility of relating lepton mixing angles with lepton mass hierarchies in a model-independent way. Guided by the existence of such relations in the quark sector, we first consider all the mixing angles, both in charged lepton and neutrino sectors to be related to the respective mass ratios. This allows us to calculate the leptonic mixing angles observed in neutrino oscillations as functions of the lightest neutrino mass. We show that for both normal and inverted hierarchical neutrino masses, this scenario does not give rise to correct leptonic mixing angles. We then show that correct leptonic mixing angles can be generated with normal hierarchical neutrino masses if the relation between mixing angle and mass ratio is restricted to 1–2 and 1–3 mixing in both charged lepton and neutrino sectors leaving the 2–3 mixing angles as free parameters. We then restrict the lightest neutrino mass as well as the difference between 2–3 mixing angles in charged lepton and neutrino sectors from the requirement of producing correct leptonic mixing angles. We constrain the lightest neutrino mass to be around 0.002 eV and leptonic Dirac CP phase [Formula: see text] such that [Formula: see text]. We also construct the leptonic mass matrices in terms of 2–3 mixing angles and lightest neutrino mass and briefly comment on the possibility of realizing texture zeros in the neutrino mass matrix.

scholarly journals The Standard Model of Particle Physics with Diracian Neutrino Sector

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 994 ◽  
Author(s):  
Theodorus Maria Nieuwenhuizen
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Mass Matrix ◽  
High Energy ◽  
Solar Neutrinos ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Sterile Neutrinos ◽  
Neutrino Sector ◽  
The Standard Model

The minimally extended standard model of particle physics contains three right handed or sterile neutrinos, coupled to the active ones by a Dirac mass matrix and mutually by a Majorana mass matrix. In the pseudo-Dirac case, the Majorana terms are small and maximal mixing of active and sterile states occurs, which is generally excluded for solar neutrinos. In a “Diracian” limit, the physical masses become pairwise degenerate and the neutrinos attain a Dirac signature. Members of a pair do not oscillate mutually so that their mixing can be undone, and the standard neutrino model follows as a limit. While two Majorana phases become physical Dirac phases and three extra mass parameters occur, a better description of data is offered. Oscillation problems are worked out in vacuum and in matter. With lepton number –1 assigned to the sterile neutrinos, the model still violates lepton number conservation and allows very feeble neutrinoless double beta decay. It supports a sterile neutrino interpretation of Earth-traversing ultra high energy events detected by ANITA.

scholarly journals Lepton number violation in a unified framework

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Yuta Kawamura ◽  
Yamato Matsuo ◽  
Takuya Morozumi ◽  
Apriadi Salim Adam ◽  
Yusuke Shimizu ◽  
...  
Keyword(s):  
Time Evolution ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Mass Term ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Mass Hierarchy ◽  
Unified Framework ◽  
Initial State ◽  
Lepton Family

Abstract We study the time evolution of lepton family number for a neutrino that forms an SU(2) doublet with a charged lepton. The lepton family number is defined through a weak basis of the SU(2) doublet in which the charged lepton mass matrix is a real and diagonal one. The lepton family number carried by the neutrino is defined with a left-handed current of the neutrino family. We study the time evolution of the lepton family number operator for the Majorana neutrino. To be definite, we introduce the mass term at $t=0$ and study the time evolution of the lepton family number for the later time. Since the operator in the flavor eigenstate is continuously connected to that of the mass eigenstate, the creation and annihilation operators for the flavor eigenstates are related to those of the mass eigenstates. The total lepton number of the Majorana neutrino is conserved. By choosing a specific flavor eigenstate of the neutrino as an initial state, we compute the time evolution of all lepton family numbers. They are sensitive to Majorana and Dirac phases and are also sensitive to the absolute mass and mass hierarchy of neutrinos.

scholarly journals THE NEUTRINOLESS DOUBLE β DECAY AND THE NEUTRINO MASS HIERARCHY

2002 ◽  
Vol 17 (14) ◽  
pp. 865-874 ◽  
Author(s):  
NAOYUKI HABA ◽  
TOMOHARU SUZUKI
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Hierarchy ◽  
Type B ◽  
Β Decay ◽  
Neutrino Mass Hierarchy ◽  
Small Magnitude ◽  
Absolute Mass ◽  
Type C ◽  
Degenerate Neutrino

Recently the evidence of the neutrinoless double β (0νββ) decay has been announced. This means that neutrinos are Majorana particles and their mass hierarchy is forced to certain patterns in the diagonal basis of charged lepton mass matrix. We estimate the magnitude of 0νββ decay in the classification of the neutrino mass hierarchy patterns as Type A, m1,2 ≪ m3, Type B, m1 ~ m2 ≫ m3, and Type C, m1 ~ m2 ~ m3, where mi is the ith generation neutrino absolute mass. The data of 0νββ decay experiment suggest that the neutrino mass hierarchy pattern should be Type B or C. Type B predicts a small magnitude of 0νββ decay which is just edge of the allowed region of experimental value in 95% c.l., where Majorana CP phases should be in a certain parameter region. Type C can induce the suitably large amount of 0νββ decay which is consistent with the experimental data, where overall scale of degenerate neutrino mass plays a crucial role, and its large value can induce the large 0νββ decay in any parameter regions of Majorana CP phases.

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