scholarly journals CP violations in a predictive A4 symmetry model

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
T Phong Nguyen ◽  
L T Hue ◽  
D T Si ◽  
T T Thuc
Keyword(s):  
Neutrino Mass ◽  
Branching Ratio ◽  
Mass Scale ◽  
Double Beta Decay ◽  
Inverted Hierarchy ◽  
Yukawa Couplings ◽  
Cp Violations ◽  
Physical Consequences ◽  
The Right ◽  
O 10

Abstract We will investigate numerically a seesaw model with $A_4$ flavor symmetry to find allowed regions satisfying the current experimental neutrino oscillation data, then use them to predict physical consequences. Namely, the lightest active neutrino mass is of the order of $\mathcal{O}(10^{-2})$ eV. The effective neutrino mass $|\langle m\rangle|$ associated with neutrinoless double beta decay is in the range $[0.002 \,\mathrm{eV},0.038\,\mathrm{eV}]$ and $[0.048\,\mathrm{eV},0.058\,\mathrm{eV}]$, corresponding to the normal and the inverted hierarchy schemes, respectively. Other relations among relevant physical quantities are shown, so that they can be determined if some of them are confirmed experimentally. The recent data of the baryon asymmetry of the Universe ($\eta_B$) can be explained via leptogenesis caused by the effect of the renormalization group evolution on the Dirac Yukawa couplings, provided the right-handed neutrino mass scale $M_0$ ranges from $\mathcal{O}(10^8)$ GeV to $\mathcal{O}(10^{12})$ GeV for $\tan\beta =3$. This allowed $M_0$ range is different from the scale of $\mathcal{O}(10^{13})$ GeV for other effects that also generate a consistent $\eta_B$ from leptogenesis. The branching ratio of the decay $ \mu \rightarrow\,e\gamma$ may reach future experimental sensitivity for very light values of $M_0$. Hence, it will be inconsistent with the $M_0$ range predicted from the $\eta_B$ data whenever this decay is detected experimentally.

scholarly journals On Q6 flavor symmetry and the breaking of μ ↔ τ symmetry

2017 ◽  
Vol 32 (28n29) ◽  
pp. 1750171 ◽  
Author(s):  
Juan Carlos Gómez-Izquierdo ◽  
F. Gonzalez-Canales ◽  
M. Mondragón
Keyword(s):  
Neutrino Mass ◽  
Mass Spectra ◽  
Mass Scale ◽  
Double Beta Decay ◽  
Supersymmetric Model ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Inverted Hierarchy ◽  
Mixing Angles ◽  
Good Agreement

In the simplest version of a [Formula: see text] flavored supersymmetric model, we analyze the leptonic masses and mixings in the framework of a soft breaking of the [Formula: see text] symmetry. This breaking is controlled by the inequality [Formula: see text] in the effective neutrino mass. As a consequence of this breaking, the reactor and atmospheric angles are deviate from [Formula: see text] and [Formula: see text], respectively. Such deviations can be enhanced or suppressed by the CP parities in the Majorana phases, so an analytic study is carried out to remark their importance to constrain the free parameters that accommodate the mixing angles. The normal hierarchy is completely discarded in this model, the inverted hierarchy is less favored than the degenerate one where the reactor and atmospheric angles are in good agreement with the experimental data. Additionally, the model predicts defined regions for the effective neutrino mass decay, the neutrino mass scale and the sum of the neutrino masses in the inverted and degenerate mass spectra. Thus, this model may be testable by future experiments that focus on neutrinoless double beta decay.

scholarly journals Relaxing cosmological neutrino mass bounds with unstable neutrinos

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Miguel Escudero ◽  
Jacobo Lopez-Pavon ◽  
Nuria Rius ◽  
Stefan Sandner
Keyword(s):  
Neutrino Mass ◽  
Particle Physics ◽  
Goldstone Boson ◽  
Mass Scale ◽  
Simple Extension ◽  
Type I ◽  
Mass Generation ◽  
Age Of The Universe ◽  
Neutrino Mass Models ◽  
The Right

Abstract At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model (ΛCDM), the Planck collaboration reports ∑mv< 0.12 eV at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe τν ≲ tU, represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state ν4 and a Goldstone boson ϕ, in which νi→ ν4ϕ decays can loosen the neutrino mass bounds up to ∑mv ∼ 1 eV, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a U(1)μ−τ flavor symmetry, which are otherwise in tension with the current bound on ∑mv.

scholarly journals NEUTRINOLESS DOUBLE BETA DECAY: AN EXTREME CHALLENGE

2013 ◽  
Vol 53 (A) ◽  
pp. 790-792
Author(s):  
Fernando Ferroni
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Neutrinoless Double Beta Decay ◽  
Mass Region ◽  
Double Beta Decay ◽  
Great Power ◽  
Inverted Hierarchy

Neutrino-less Double Beta Decay is the only known way to possibly resolve the nature of neutrino mass. The chances to cover the mass region predicted by the inverted hierarchy require a step forward in detector capability. A possibility is to make use of scintillating bolometers. These devices shall have a great power in distinguishing signals from alfa particles from those induced by electrons. This feature might lead to an almost background-free experiment. Here the Lucifer concept will be introduced and the prospects related to this project will be discussed.

scholarly journals TRIBIMAXIMAL MIXING IN NEUTRINO MASS MATRICES WITH TEXTURE ZEROS OR VANISHING MINORS

2011 ◽  
Vol 26 (07) ◽  
pp. 501-514 ◽  
Author(s):  
S. DEV ◽  
SHIVANI GUPTA ◽  
RADHA RAMAN GAUTAM
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Scale ◽  
Neutrino Mass Matrix ◽  
Seesaw Mechanism ◽  
Majorana Mass ◽  
Absolute Mass ◽  
Mass Matrices ◽  
The One ◽  
The Right

We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with μτ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors on the right-handed Majorana mass matrix having μτ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with μτ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass Mee, the absolute mass scale and the Majorana-type CP violating phases.

scholarly journals CONSTRAINTS ON TeV SCALE MAJORANA NEUTRINO PHENOMENOLOGY FROM THE VACUUM STABILITY OF THE HIGGS

2013 ◽  
Vol 28 (11) ◽  
pp. 1350032 ◽  
Author(s):  
JOYDEEP CHAKRABORTTY ◽  
MOUMITA DAS ◽  
SUBHENDRA MOHANTY
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Stability Condition ◽  
Branching Ratio ◽  
Neutrinoless Double Beta Decay ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Heavy Neutrino ◽  
Neutrino Mixing ◽  
Vacuum Stability

The vacuum stability condition of the Standard Model (SM) Higgs potential with mass in the range of 124–127 GeV puts an upper bound on the Dirac mass of the neutrinos. We study this constraint with the right-handed neutrino masses up to TeV scale. The heavy neutrinos contribute to ΔL = 2 processes like neutrinoless double beta decay and same-sign-dilepton (SSD) production in the colliders. The vacuum stability criterion also restricts the light-heavy neutrino mixing and constrains the branching ratio (BR) of lepton flavor-violating process, like μ→eγ mediated by the heavy neutrinos. We show that neutrinoless double beta decay with a lifetime ~1025 years can be observed if the lightest heavy neutrino mass is <4.5 TeV. We show that the vacuum stability condition and the experimental bound on μ→e γ together put a constrain on heavy neutrino mass MR>3.3 TeV. Finally we show that the observation of SSDs associated with jets at the LHC needs much larger luminosity than available at present. We have estimated the possible maximum cross-section for this process at the LHC and show that with an integrated luminosity 100 fb-1 it may be possible to observe the SSD signals as long as MR < 400 GeV.

scholarly journals Leptogenesis and fermion mass fit in a renormalizable SO(10) model

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
V. Suryanarayana Mummidi ◽  
Ketan M. Patel
Keyword(s):  
Numerical Solutions ◽  
Double Beta Decay ◽  
Fermion Mass ◽  
Strong Correlations ◽  
Yukawa Couplings ◽  
Mixing Parameters ◽  
Fermion Masses ◽  
The Standard Model ◽  
The Right ◽  
Yukawa Sector

Abstract A non-supersymmetric renormalizable SO(10) model is investigated for its viability in explaining the observed fermion masses and mixing parameters along with the baryon asymmetry produced via thermal leptogenesis. The Yukawa sector of the model consists of complex 10H and $$ {\overline{126}}_H $$ 126 ¯ H scalars with a Peccei-Quinn like symmetry and it leads to strong correlations among the Yukawa couplings of all the standard model fermions including the couplings and masses of the right-handed (RH) neutrinos. The latter implies the necessity to include the second lightest RH neutrino and flavor effects for the precision computation of leptogenesis. We use the most general density matrix equations to calculate the temperature evolution of flavoured leptonic asymmetry. A simplified analytical solution of these equations, applicable to the RH neutrino spectrum predicted in the model, is also obtained which allows one to fit the observed baryon to photon ratio along with the other fermion mass observables in a numerically efficient way. The analytical and numerical solutions are found to be in agreement within a factor of $$ \mathcal{O}(1) $$ O 1 . We find that the successful leptogenesis in this model does not prefer any particular value for leptonic Dirac and Majorana CP phases and the entire range of values of these observables is found to be consistent. The model specifically predicts (a) the lightest neutrino mass $$ {m}_{v_1} $$ m v 1 between 2–8 meV, (b) the effective mass of neutrinoless double beta decay mββ between 4–10 meV, and (c) a particular correlation between the Dirac and one of the Majorana CP phases.

Trimaximal mixing with one texture zero of the inverse neutrino mass matrix

2020 ◽  
Vol 35 (07) ◽  
pp. 2050039
Author(s):  
Zhen-Hua Zhao ◽  
Xin Zhang ◽  
Shan-Shan Jiang ◽  
Chong-Xing Yue
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Mass Matrix ◽  
Mass Scale ◽  
Double Beta Decay ◽  
Neutrino Mass Matrix ◽  
Inverse Matrix ◽  
Texture Zero ◽  
Matrix Formula ◽  
Absolute Neutrino Mass

In this paper, we study the phenomenological implications of enforcing one texture zero on the inverse matrix of the neutrino mass matrix [Formula: see text] that can lead to the trimaximal mixing. It is found that the condition of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] or [Formula: see text] can hold in the case of normal neutrino mass ordering, while the condition of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] or [Formula: see text] can hold in the case of inverted neutrino mass ordering, where [Formula: see text] (for [Formula: see text], [Formula: see text]) denotes the [Formula: see text] entry of the inverse matrix of [Formula: see text]. The ranges of the absolute neutrino mass scale and three CP phases for these cases to hold are studied in some detail. The implications of these cases for the effective neutrino mass [Formula: see text] which controls the rates of the neutrino-less double beta decay processes are also given.

scholarly journals Neutrino Mass, the Right-Handed Interaction and the Double Beta Decay. II: -- General Properties and Data Analysis --

1982 ◽  
Vol 68 (1) ◽  
pp. 348-348 ◽  
Author(s):  
M. Doi ◽  
T. Kotani ◽  
H. Nishiura ◽  
K. Okuda ◽  
E. Takasugi
Keyword(s):  
Data Analysis ◽  
Beta Decay ◽  
Neutrino Mass ◽  
Double Beta Decay ◽  
General Properties ◽  
The Right

scholarly journals High Scale Type-II Seesaw, Dominant Double Beta Decay within Cosmological Bound and LFV Decays in SU(‎5)

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
M. K. Parida ◽  
Rajesh Satpathy
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Double Beta Decay ◽  
Type I ◽  
Mass Hierarchy ◽  
Type Ii ◽  
Inverted Hierarchy ◽  
Mass Generation ◽  
Neutrino Mass Generation ◽  
Physical Phenomena

Very recently novel implementation of type-II seesaw mechanism for neutrino mass has been proposed in SU(5) grand unified theory with a number of desirable new physical phenomena beyond the standard model. Introducing heavy right-handed neutrinos and extra fermion singlets, in this work we show how the type-I seesaw cancellation mechanism works in this SU(5) framework. Besides predicting verifiable LFV decays, we further show that the model predicts dominant double beta decay with normal hierarchy or inverted hierarchy of active light neutrino masses in concordance with cosmological bound. In addition a novel right-handed neutrino mass generation mechanism, independent of type-II seesaw predicted mass hierarchy, is suggested in this work.

scholarly journals Neutrino Mass, the Right-Handed Interaction and the Double Beta Decay. II: General Properties and Data Analysis

1981 ◽  
Vol 66 (5) ◽  
pp. 1765-1788 ◽  
Author(s):  
M. Doi ◽  
T. Kotani ◽  
H. Nishiura ◽  
K. Okuda ◽  
E. Takasugi
Keyword(s):  
Data Analysis ◽  
Beta Decay ◽  
Neutrino Mass ◽  
Double Beta Decay ◽  
General Properties ◽  
The Right
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