Effective ℒ5 Lagrangian and masses of Majorana neutrinos

2021 ◽  
pp. 2150081
Author(s):  
Olakanmi F. Akinto ◽  
Farida Tahir
Keyword(s):  
Mass Formula ◽  
Symmetric Matrix ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Neutrino Masses ◽  
Unified Theory ◽  
Grand Unified Theory ◽  
Majorana Neutrinos ◽  
Cosmological Data ◽  
Good Agreement

Using the fact that neutrinos only participate in weak and gravitational interactions, we explore the possibility of having their masses emerged at the intersection between extended electroweak theory and theory of gravity. We describe how these two seemingly incompatible theories could be embedded in a lepton-number violating 5-dimensional Lagrangian [Formula: see text]. A peculiar feature of this approach is its ability to generate effective Majorana neutrino masses via the spontaneous symmetry breaking (SSB) of Grand Unified Theory (GUT), [Formula: see text] and 4[Formula: see text] symmetric matrix of gravitational couplings. Within the purview of this theoretical framework, we obtain values for the effective Majorana mass [Formula: see text][Formula: see text]meV, and the Majorana neutrino masses [Formula: see text][Formula: see text]meV, [Formula: see text][Formula: see text]meV, [Formula: see text][Formula: see text]meV, [Formula: see text][Formula: see text]meV and [Formula: see text][Formula: see text]eV. Our results are in good agreement with both experimental and cosmological data.

scholarly journals CONSTRAINTS OF MIXING ANGLES FROM LEPTON NUMBER VIOLATING PROCESSES

1999 ◽  
Vol 14 (06) ◽  
pp. 433-445 ◽  
Author(s):  
HIROYUKI NISHIURA ◽  
KOUICHI MATSUDA ◽  
TAKESHI FUKUYAMA
Keyword(s):  
Beta Decay ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Left Handed ◽  
Majorana Neutrinos ◽  
Mixing Matrix ◽  
Lepton Number Violating

We discuss the constraints of lepton mixing angles from lepton number violating processes such as neutrinoless double beta decay, μ--e+ conversion and K decay, K-→π+μ-μ- which are allowed only if neutrinos are Majorana particles. The rates of these processes are proportional to the averaged neutrino mass defined by [Formula: see text] in the absence of right-handed weak coupling. Here a, b(j) are flavor(mass) eigenstates and Uaj is the left-handed lepton mixing matrix. We give general conditions imposed on <mν>ab in terms of mi, lepton mixing angles and CP violating phases (three phases in Majorana neutrinos). These conditions are reduced to the constraints among mi, lepton mixing angles and <mν>ab which are irrelevant to the concrete values of CP phases. Given a <mν>ab experimentally, these conditions constrain mi and the lepton mixing angles. Though these constraints are still loose except for neutrinoless double beta decay, they will become helpful through rapid improvements of experiments. By using these constraints we also derive the limits on averaged neutrino masses for μ--e+ conversion and K decay, K-→π+μ-μ-, respectively. We also present the bounds for CP phases in terms of mi, mixing angles and <mν>ab.

Vanishing effective Majorana neutrino mass and light sterile neutrinos

2016 ◽  
Vol 31 (06) ◽  
pp. 1650040 ◽  
Author(s):  
Surender Verma
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Majorana Neutrino ◽  
Recent Measurement ◽  
Neutrino Masses ◽  
Sterile Neutrinos ◽  
Majorana Mass ◽  
Scatter Plots ◽  
Majorana Neutrino Mass ◽  
Neutrino Masses And Mixings

We examine the possibility of vanishing effective Majorana mass [Formula: see text] in the presence of one or two sterile neutrinos taking into account the recent data on neutrino masses and mixings, particularly, on [Formula: see text]. Also, within the framework of standard three active neutrinos, we find that effective Majorana mass [Formula: see text] can be vanishingly small if neutrino masses observe normal hierarchy. However, the same is not valid for inverted hierarchical neutrino masses. The predictions for Majorana phases [Formula: see text] and [Formula: see text] have also been obtained and shown as scatter plots. We also examine the condition [Formula: see text] within the framework wherein fermion sector has been extended by the addition of either one or two sterile neutrinos. The condition of vanishing effective Majorana mass is found to be inconsistent with the recent measurement of [Formula: see text] in these classes of models except for [Formula: see text], [Formula: see text] neutrino mass scheme for small values of the lightest neutrino mass, [Formula: see text].

Neutrinoless double-beta decays: New insights

2017 ◽  
Vol 32 (14) ◽  
pp. 1730011 ◽  
Author(s):  
Z. Z. Xing ◽  
Z. H. Zhao
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Three Dimensional ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Two Dimensional ◽  
Mixing Angles ◽  
Flavor Mixing ◽  
Majorana Neutrino Mass ◽  
Beta Decays

We give some new insights into the effective Majorana neutrino mass [Formula: see text] responsible for the neutrinoless double-beta [Formula: see text] decays. We put forward a three-dimensional way of plotting [Formula: see text] against the lightest neutrino mass and the Majorana phases, which can provide more information as compared with the two-dimensional one. With the help of such graphs we discover a novel threshold of [Formula: see text] in terms of the neutrino masses and flavor mixing angles: [Formula: see text] in connection with [Formula: see text] and [Formula: see text], which can be used to signify observability of the future [Formula: see text]-decay experiments. Fortunately, the possibility of [Formula: see text] turns out to be very small, promising a hopeful prospect for the [Formula: see text]-decay searches.

scholarly journals SO(10) × S4 grand unified theory of flavour and leptogenesis

2017 ◽  
Vol 2017 (12) ◽  
Author(s):  
Francisco J. de Anda ◽  
Stephen F. King ◽  
Elena Perdomo
Keyword(s):  
Neutrino Mass ◽  
Discrete Group ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Type I ◽  
Unified Theory ◽  
Grand Unified Theory ◽  
Oscillation Phase ◽  
Seesaw Mechanism ◽  
Natural Range

Abstract We propose a Grand Unified Theory of Flavour, based on SO(10) together with a non-Abelian discrete group S 4, under which the unified three quark and lepton 16-plets are unified into a single triplet 3′. The model involves a further discrete group ℤ 4 R  × ℤ 4 3 which controls the Higgs and flavon symmetry breaking sectors. The CSD2 flavon vacuum alignment is discussed, along with the GUT breaking potential and the doublet-triplet splitting, and proton decay is shown to be under control. The Yukawa matrices are derived in detail, from renormalisable diagrams, and neutrino masses emerge from the type I seesaw mechanism. A full numerical fit is performed with 15 input parameters generating 19 presently constrained observables, taking into account supersymmetry threshold corrections. The model predicts a normal neutrino mass ordering with a CP oscillation phase of 260°, an atmospheric angle in the first octant and neutrinoless double beta decay with m ββ = 11 meV. We discuss N 2 leptogenesis, which fixes the second right-handed neutrino mass to be M 2 ≃ 2 × 1011 GeV, in the natural range predicted by the model.

scholarly journals The neutrino masses in SO(10) grand unified theory

1987 ◽  
Vol 188 (4) ◽  
pp. 455-461 ◽  
Author(s):  
G.K. Leontaris ◽  
J.D. Vergados
Keyword(s):  
Neutrino Masses ◽  
Unified Theory ◽  
Grand Unified Theory

scholarly journals Neutrinoless double-beta decay: A probe of physics beyond the Standard Model

2015 ◽  
Vol 30 (04n05) ◽  
pp. 1530001 ◽  
Author(s):  
S. M. Bilenky ◽  
C. Giunti
Keyword(s):  
Standard Model ◽  
Present Status ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
Β Decay ◽  
The Standard Model ◽  
Double Β Decay

In the Standard Model the total lepton number is conserved. Thus, neutrinoless double-β decay, in which the total lepton number is violated by two units, is a probe of physics beyond the Standard Model. In this review we consider the basic mechanism of neutrinoless double-β decay induced by light Majorana neutrino masses. After a brief summary of the present status of our knowledge of neutrino masses and mixing and an introduction to the seesaw mechanism for the generation of light Majorana neutrino masses, in this review we discuss the theory and phenomenology of neutrinoless double-β decay. We present the basic elements of the theory of neutrinoless double-β decay, our view of the present status of the challenging problem of the calculation of the nuclear matrix element of the process and a summary of the experimental results.

On the Majorana neutrinos and neutrinoless double beta decays

2015 ◽  
Vol 30 (25) ◽  
pp. 1530019 ◽  
Author(s):  
Zhi-Zhong Xing ◽  
Ye-Ling Zhou
Keyword(s):  
Complex Plane ◽  
Mass Formula ◽  
New Physics ◽  
Lepton Number ◽  
Majorana Mass ◽  
Majorana Neutrinos ◽  
Massive Neutrinos ◽  
Beta Decays ◽  
Lepton Number Violating

The neutrinoless double-beta [Formula: see text] decay is a lepton-number-violating process which is experimentally unique for identifying the Majorana nature of massive neutrinos. We give a brief overview of some theoretical aspects of this process. In particular, a novel “coupling-rod” diagram is introduced to describe the effective Majorana mass [Formula: see text] in the complex plane. Possible contributions of new physics to [Formula: see text] are also discussed.

scholarly journals SUPERSYMMETRIC HIGGS TRIPLETS AND BILINEAR R-PARITY NONCONSERVATION

2002 ◽  
Vol 17 (19) ◽  
pp. 1259-1261 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Tree Level ◽  
Neutrino Masses ◽  
Parity Nonconservation ◽  
Particle Interactions

The supersymmetric standard model of particle interactions is extended to include two Higgs triplet superfields at the TeV scale, carrying two units of lepton number. Realistic tree-level Majorana neutrino masses are obtained in the presence of soft, i.e. bilinear, R-parity nonconservation.

scholarly journals MODEL FOR SMALL NEUTRINO MASSES AT THE TeV SCALE

2002 ◽  
Vol 17 (13) ◽  
pp. 771-778 ◽  
Author(s):  
SALAH NASRI ◽  
SHERIF MOUSSA
Keyword(s):  
Standard Model ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Neutrino Masses ◽  
Mass Generation ◽  
Seesaw Mechanism ◽  
Left Handed ◽  
The Standard Model ◽  
Neutrino Mass Generation ◽  
The One

We propose a model for neutrino mass generation in which no physics beyond a TeV is required. We extend the standard model by adding two charged singlet fields with lepton number two. Dirac neutrino masses mνD ≤ MeV are generated at the one-loop level. Small left-handed Majorana neutrino masses can be generated via the seesaw mechanism with right-handed neutrino masses MR of order TeV scale.

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