scholarly journals Minimal scoto-seesaw mechanism with spontaneous CP violation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
D. M. Barreiros ◽  
F. R. Joaquim ◽  
R. Srivastava ◽  
J. W. F. Valle
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Seesaw Mechanism ◽  
Cosmological Observations ◽  
Scalar Singlet

Abstract We propose simple scoto-seesaw models to account for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal $$ {\mathcal{Z}}_8 $$ Z 8 discrete symmetry, broken to a residual $$ {\mathcal{Z}}_2 $$ Z 2 subgroup responsible for stabilizing dark matter. CP is broken spontaneously via the complex vacuum expectation value of a scalar singlet, inducing leptonic CP-violating effects. We find that the imposed $$ {\mathcal{Z}}_8 $$ Z 8 symmetry pushes the values of the Dirac CP phase and the lightest neutrino mass to ranges already probed by ongoing experiments, so that normal-ordered neutrino masses can be cornered by cosmological observations and neutrinoless double beta decay experiments.

scholarly journals Modulus τ linking leptonic CP violation to baryon asymmetry in A4 modular invariant flavor model

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Hiroshi Okada ◽  
Yusuke Shimizu ◽  
Morimitsu Tanimoto ◽  
Takahiro Yoshida
Keyword(s):  
Cp Violation ◽  
Effective Mass ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Baryon Asymmetry ◽  
Neutrino Masses ◽  
Normal Hierarchy ◽  
Modular Invariant ◽  
Mixing Angles ◽  
Expectation Value

Abstract We propose an A4 modular invariant flavor model of leptons, in which both CP and modular symmetries are broken spontaneously by the vacuum expectation value of the modulus τ. The value of the modulus τ is restricted by the observed lepton mixing angles and lepton masses for the normal hierarchy of neutrino masses. The predictive Dirac CP phase δCP is in the ranges [0°, 50°], [170°, 175°] and [280°, 360°] for Re [τ] < 0, and [0°, 80°], [185°, 190°] and [310°, 360°] for Re [τ] > 0. The sum of three neutrino masses is predicted in [60, 84] meV, and the effective mass for the 0νββ decay is in [0.003, 3] meV. The modulus τ links the Dirac CP phase to the cosmological baryon asymmetry (BAU) via the leptogenesis. Due to the strong wash-out effect, the predictive baryon asymmetry YB can be at most the same order of the observed value. Then, the lightest right-handed neutrino mass is restricted in the range of M1 = [1.5, 6.5] × 1013 GeV. We find the correlation between the predictive YB and the Dirac CP phase δCP. Only two predictive δCP ranges, [5°, 40°] (Re [τ] > 0) and [320°, 355°] (Re [τ] < 0) are consistent with the BAU.

scholarly journals Spontaneous CP violation by modulus τ in A4 model of lepton flavors

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Hiroshi Okada ◽  
Morimitsu Tanimoto
Keyword(s):  
Cp Violation ◽  
Confidence Level ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
The Other ◽  
Neutrino Masses ◽  
Normal Hierarchy ◽  
Expectation Value ◽  
Invariant Model ◽  
Cp Symmetry

Abstract We discuss the modular A4 invariant model of leptons combining with the generalized CP symmetry. In our model, both CP and modular symmetries are broken spontaneously by the vacuum expectation value of the modulus τ. The source of the CP violation is a non-trivial value of Re[τ] while other parameters of the model are real. The allowed region of τ is in very narrow one close to the fixed point τ = i for both normal hierarchy (NH) and inverted ones (IH) of neutrino masses. The CP violating Dirac phase δCP is predicted clearly in [98°, 110°] and [250°, 262°] for NH at 3 σ confidence level. On the other hand, δCP is in [95°, 100°] and [260°, 265°] for IH at 5 σ confidence level. The predicted ∑mi is in [82, 102] meV for NH and ∑mi = [134, 180] meV for IH. The effective mass 〈mee〉 for the 0νββ decay is predicted in [12.5, 20.5] meV and [54, 67] meV for NH and IH, respectively.

FERMION SPECTRA AND KM MATRICES IN A LEFT-RIGHT SYMMETRIC MODEL FROM CALABI-YAU STRING COMPACTIFICATION

1993 ◽  
Vol 08 (29) ◽  
pp. 5235-5263
Author(s):  
CHUICHIRO HATTORI ◽  
MASAHISA MATSUDA ◽  
TAKEO MATSUOKA ◽  
DAIZO MOCHINAGA
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Current Data ◽  
Fourth Generation ◽  
Spontaneous Breaking ◽  
Neutrino Masses ◽  
Symmetric Model ◽  
Seesaw Mechanism ◽  
Flavor Changing ◽  
O 10

We study a left-right symmetric type of the effective low-energy theory induced from the four-generation superstring model. The spontaneous breaking of the R-parity occurs through a nonzero vacuum expectation value (VEV) of the fourth generation right-handed sneutrino (νR). It is predicted that the lightest chargino is lighter than 113 GeV. By virtue of the seesaw mechanism we can explain the smallness of neutrino masses for three generations and the largeness of the fourth generation neutrino mass. The mixing in the color-singlet sector yields nontrivial KM matrices which bring about flavor-changing interactions. If we take νR=O(10 TeV ), our results are consistent with the current data except for the solar neutrino problem.

scholarly journals SCOTOGENIC A4 NEUTRINO MODEL FOR NONZERO θ13 AND LARGE δCP

2012 ◽  
Vol 27 (23) ◽  
pp. 1250134 ◽  
Author(s):  
ERNEST MA ◽  
ALEXANDER NATALE ◽  
AHMED RASHED
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Discrete Symmetry ◽  
Neutrino Masses ◽  
Degenerate Solutions

Assuming that neutrinos acquire radiative seesaw Majorana masses through their interactions with dark matter, i.e. scotogenic from the Greek "scotos" meaning darkness, and using the non-Abelian discrete symmetry A4, we propose a model of neutrino masses and mixing with nonzero θ13 and necessarily large leptonic CP violation, allowing both the normal and inverted hierarchies of neutrino masses, as well as quasi-degenerate solutions.

scholarly journals THE HIGGS SECTOR AND ELECTRON ELECTRIC DIPOLE MOMENT IN NEXT-TO-MINIMAL SUPERSYMMETRY WITH EXPLICIT CP VIOLATION

2006 ◽  
Vol 21 (03) ◽  
pp. 243-264 ◽  
Author(s):  
MÜGE BOZ
Keyword(s):  
Dipole Moment ◽  
Cp Violation ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Higgs Field ◽  
Higgs Sector ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Supersymmetric Model ◽  
Numerical Predictions

We study the explicit CP violation of the Higgs sector in the next-to-minimal supersymmetric model with a gauge singlet Higgs field. Our numerical predictions show that electric dipole moment of electron lies around the present experimental upper limits. The mass of the lightest Higgs boson is quite sensitive to the CP violating phases in the theory. It is observed that as the vacuum expectation value of the singlet gets higher values, CP violation increases.

scholarly journals Modular $S_3$-invariant flavor model in SU(5) grand unified theory

2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Tatsuo Kobayashi ◽  
Yusuke Shimizu ◽  
Kenta Takagi ◽  
Morimitsu Tanimoto ◽  
Takuya H. Tatsuishi
Keyword(s):  
Modular Forms ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Double Beta Decay ◽  
Unified Theory ◽  
Grand Unified Theory ◽  
Mass Matrices ◽  
Charge Parity ◽  
Charged Leptons ◽  
Leptonic Charge

Abstract We present a flavor model with $S_3$ modular invariance in the framework of SU(5) grand unified theory (GUT). The $S_3$ modular forms of weights $2$ and $4$ give the quark and lepton mass matrices with a common complex parameter, the modulus $\tau$. The GUT relation of down-type quarks and charged leptons is imposed by the vacuum expectation value (VEV) of the adjoint 24-dimensional Higgs multiplet in addition to the VEVs of $5$ and $\bar 5$ Higgs multiplets of SU(5). The observed Cabibbo–Kobayashi–Maskawa and Pontecorvo–Maki–Nakagawa–Sakata mixing parameters as well as the mass eigenvalues are reproduced properly. We discuss the leptonic charge–parity phase and the effective mass of the neutrinoless double beta decay with the sum of neutrino masses.

scholarly journals EXPERIMENTAL NEUTRINO PHYSICS

2005 ◽  
Vol 20 (14) ◽  
pp. 2895-2906
Author(s):  
K. Zuber
Keyword(s):  
Neutrino Physics ◽  
Cp Violation ◽  
Rest Mass ◽  
Double Beta Decay ◽  
Matrix Elements ◽  
Mass Measurements ◽  
Mixing Angle ◽  
Cosmological Observations ◽  
Absolute Mass ◽  
Mixing Matrix

The current experimental status of neutrino physics is reviewed. It contains the evidences for a non-vanishing neutrino rest mass from neutrino oscillation searches. In addition an outlook is given on determining the various mixing matrix elements and mass differences more precisely with new experiments. Of special interest is the value of the mixing angle θ13 determining the possibility of detecting leptonic CP violation in the future. The prospect for absolute mass measurements using beta and double beta decay as well as cosmological observations is presented.

scholarly journals QUARK MASS HIERARCHY AND CP VIOLATION IN LOW ENERGY SUPERSYMMETRY

1996 ◽  
Vol 11 (23) ◽  
pp. 4307-4319 ◽  
Author(s):  
CHUN LIU
Keyword(s):  
Cp Violation ◽  
Quark Mass ◽  
Neutral Current ◽  
Vacuum Expectation ◽  
Discrete Symmetry ◽  
Low Energy ◽  
Tree Level ◽  
Mass Hierarchy ◽  
Family Symmetry ◽  
Flavor Changing

A pattern of quark mass hierarchy and CP violation within the framework of low energy supersymmetry is described. By assuming some discrete symmetry among the three families, the quarks of the third family obtain masses at tree level. The second family obtains masses radiatively at one-loop level due to the soft breaking of the family symmetry. At this level, the first family remains massless by some degeneracy conditions of the squarks. As a result of R parity violation, the sneutrino vacuum expectation values are nonvanishing. CP violation occurs through the superweak sneutrino exchange. This picture is consistent with the experiments on the flavor-changing neutral current.

SPONTANEOUS CP VIOLATION IN A TWO-GENERATION LEFT-RIGHT SYMMETRIC MODEL WITH TWO HIGGS BI-DOUBLETS

1992 ◽  
Vol 07 (34) ◽  
pp. 3179-3186 ◽  
Author(s):  
AMBAR GHOSAL ◽  
ASIM K. RAY ◽  
SASWATI SARKAR
Keyword(s):  
Cp Violation ◽  
Relative Phase ◽  
Vacuum Expectation ◽  
Discrete Symmetry ◽  
Tree Level ◽  
Model Parameters ◽  
Symmetric Model ◽  
Expectation Values ◽  
Flavor Changing ◽  
Experimental Values

We discuss a two-generation left-right symmetric model with two Higgs bi-doublets and a discrete symmetry to show that spontaneous CP violation arises as a result of soft breaking of the discrete symmetry. The contributions to the CP violation parameter ε in the [Formula: see text] transition come from the box diagrams due to WL-WR exchanges as well as from the mixing of the real and imaginary parts of the flavor changing neutral Higgs at the tree level and both contributions depend on the relative phase difference between the vacuum expectation values (vevs) of the relevant neutral Higgs scalars. Other CP violating effects in the model are consistent with their experimental values for the appropriate choice of the model parameters. The extension of the model to the realistic case of three generations of fermions does not appreciably change the phenomenology of the model.

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.

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