IMPLICATIONS OF μ ↔ τ SYMMETRY ON NEUTRINOS AND LEPTOGENESIS

2005 ◽  
Vol 20 (27) ◽  
pp. 6258-6267 ◽  
Author(s):  
SALAH NASRI
Keyword(s):  
Cp Violation ◽  
Symmetry Breaking ◽  
Neutrino Oscillation ◽  
Simple Form ◽  
Lepton Sector ◽  
Lepton Asymmetry ◽  
Mixing Angle ◽  
Model Based ◽  
Breaking Parameter ◽  
The Universe

We discuss a model based on μ ↔ τ symmetry acting in the lepton sector, which leads to maximal atmospheric mixing angle and θ13 = 0. We show that in the symmetric limit the lepton asymmetry ∊l of the universe can be given in a simple form in terms of the neutrino oscillation parameters. We also find that for the case of two right handed neutrinos ∊l, constrain the symmetry breaking parameter θ13 to be in range 0.1 to 0.2 depending on the leptonic CP violation phase.

scholarly journals Significance of Broken μ − τ Symmetry in Correlating δ CP , θ 13 , Lightest Neutrino Mass, and Neutrinoless Double Beta Decay 0 ν β β

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Gayatri Ghosh
Keyword(s):  
Cp Violation ◽  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Parameter Space ◽  
Double Beta Decay ◽  
Light Neutrino ◽  
Type I ◽  
Mixing Angle ◽  
Reactor Mixing ◽  
The Universe

Leptonic CP violating phase δ CP in the light neutrino sector and leptogenesis via present matter-antimatter asymmetry of the Universe entails each other. Probing CP violation in light neutrino oscillation is one of the challenging tasks today. The reactor mixing angle θ 13 measured in reactor experiments, LBL, and DUNE with high precision in neutrino experiments indicates towards the vast dimensions of scope to detect δ CP . The correlation between leptonic Dirac CPV phase δ CP , reactor mixing angle θ 13 , lightest neutrino mass m 1 , and matter-antimatter asymmetry of the Universe within the framework of μ − τ symmetry breaking assuming the type I seesaw dominance is extensively studied here. Here, a SO(10) GUT model with flavor μ − τ symmetry is considered. In this work, the idea is to link baryogenesis through leptogenesis and the hint of CP violation in the neutrino oscillation data to a breaking of the mu-tau symmetry. Small tiny breaking of the μ − τ symmetry allows a large Dirac CP violating phase in neutrino oscillation which in turn is characterized by awareness of measured value of θ 13 and to provide a hint towards a better understanding of the experimentally observed near-maximal value of ν μ − ν τ mixing angle θ 23 ≃ π / 4 . Precise breaking of the μ − τ symmetry is achieved by adding a 120-plet Higgs to the 10 + 1 2 ¯ 6 -dimensional representation of Higgs. The estimated three-dimensional density parameter space of the lightest neutrino mass m 1 , δ CP , and reactor mixing angle θ 13 is constrained here for the requirement of producing the observed value of baryon asymmetry of the Universe through the mechanism of leptogenesis. Carrying out numerical analysis, the allowed parameter space of m 1 , δ CP , and θ 13 is found out which can produce the observed baryon to photon density ratio of the Universe.

SO(10) GUT's, Neutrinos and LFV

2005 ◽  
Vol 20 (14) ◽  
pp. 3118-3120
Author(s):  
Mu-Chun Chen ◽  
K. T. Mahanthappa
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Symmetry Breaking ◽  
Decay Rate ◽  
Next Generation ◽  
Mixing Angles ◽  
Lepton Flavor ◽  
Model Based ◽  
The Masses ◽  
The Universe

A model based on SO(10) × SU(2)F having symmetric mass textures with 5 zeros is constructed. The symmetric mass textures arising from the left-right symmetry breaking chain of SO (10) give rise to good predictions for the masses, mixing angles and CP violation measures in the quark and lepton sectors, all in agreement with the most up-to-date experimental data within 1 σ. Various lepton flavor violating decays in our model are also investigated. Unlike in models with lop-sided textures, our prediction for the decay rate of μ → e γ is much suppressed and yet it is large enough to be probed by the next generation of experiments. The observed baryonic asymmetry in the Universe can be accommodated utilizing soft leptogenesis.

scholarly journals Prospects for Neutrino Oscillation Physics

2013 ◽  
Vol 2013 ◽  
pp. 1-29 ◽  
Author(s):  
Silvia Pascoli ◽  
Thomas Schwetz
Keyword(s):  
Neutrino Oscillation ◽  
Mass Hierarchy ◽  
Lepton Sector ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Long Baseline ◽  
Reactor Neutrinos ◽  
Near Term

Recently the last unknown lepton mixing angleθ13has been determined to be relatively large, not too far from its previous upper bound. This opens exciting possibilities for upcoming neutrino oscillation experiments towards addressing fundamental questions, among them the type of the neutrino mass hierarchy and the search for CP violation in the lepton sector. In this paper we review the phenomenology of neutrino oscillations, focusing on subleading effects, which will be the key towards these goals. Starting from a discussion of the present determination of three-flavour oscillation parameters, we give an outlook on the potential of near-term oscillation physics as well as on the long-term program towards possible future precision oscillation facilities. We discuss accelerator-driven long-baseline experiments as well as nonaccelerator possibilities from atmospheric and reactor neutrinos.

scholarly journals A Comprehensive Study of the Discovery Potential of NOνA, T2K, and T2HK Experiments

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
C. Soumya ◽  
K. N. Deepthi ◽  
R. Mohanta
Keyword(s):  
Cp Violation ◽  
Neutrino Oscillation ◽  
Recent Measurement ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Discovery Potential ◽  
Reactor Mixing ◽  
Better Than ◽  
Comprehensive Study

With the recent measurement of reactor mixing angleθ13the knowledge of neutrino oscillation parameters has improved significantly except the CP violating phaseδCP, mass hierarchy, and the octant of the atmospheric mixing angleθ23. Many dedicated experiments are proposed to determine these parameters which may take at least 10 years from now to become operational. It is therefore very crucial to use the results from the existing experiments to see whether we can get even partial answers to these questions. In this paper we study the discovery potential of the ongoing NOνA and T2K experiments as well as the forthcoming T2HK experiment in addressing these questions. In particular, we evaluate the sensitivity of NOνA to determine neutrino mass hierarchy, octant degeneracy, andδCPafter running for its scheduled period of 3 years in neutrino mode and 3 years in antineutrino mode. We then extend the analysis to understand the discovery potential if the experiments will run for (5ν+5ν¯) years and (7ν+3ν¯) years. We also show how the sensitivity improves when we combine the data from NOνA, T2K, and T2HK experiments with different combinations of run period. The CP violation sensitivity is marginal for T2K and NOνA experiments even for ten-year data taking of NOνA. T2HK has a significance above5σfor a fraction of two-fifths values of theδCPspace. We also find thatδCPcan be determined to be better than 35°, 21°, and 9° for all values ofδCPfor T2K, NOνA, and T2HK respectively.

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 UNVEILING NEUTRINO MIXING AND LEPTONIC CP VIOLATION

2005 ◽  
Vol 20 (01) ◽  
pp. 1-17 ◽  
Author(s):  
OLGA MENA
Keyword(s):  
Cp Violation ◽  
Neutrino Oscillation ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Long Baseline ◽  
Neutrino Experiments ◽  
Two Parameters ◽  
Present Understanding ◽  
Neutrino Masses And Mixings

We review the present understanding of neutrino masses and mixings, discussing what are the unknowns in the three-family oscillation scenario. Despite the anticipated success coming from the planned long baseline neutrino experiments in unraveling the leptonic mixing sector, there are two important unknowns which may remain obscure: the mixing angle θ13 and the CP-phase δ. The measurement of these two parameters has led us to consider the combination of superbeams and neutrino factories as the key to unveil the neutrino oscillation picture.

scholarly journals Combined Sensitivity of T2K-II and NOνA Experiments to CP Violation in Lepton Sector

2018 ◽  
Vol 28 (4) ◽  
pp. 337
Author(s):  
Tran Van Ngoc ◽  
Cao Van Son ◽  
Nguyen Thi Hong Van
Keyword(s):  
Cp Violation ◽  
Neutrino Oscillation ◽  
Lepton Sector ◽  
Total Exposure ◽  
Long Baseline ◽  
Systematic Uncertainties ◽  
The World ◽  
Run Up

In this paper, we study the combined sensitivity of T2K-II and NOvA, the world leading long-baseline neutrino oscillation experiments, to CP violation in lepton sector. By operating until the year 2026, T2K-II is expected to collect a total exposure of \(20 \times 10^{21}\) protons-on-target. Meanwhile, NO$\nu$A experiment plan to expend the run up to 2024. By combining T2K-II and NO\(\nu\)A with an ultimate constraint from reactor, the sensitivity to CP-violation is expected to exceed $4\sigma$ C.L. It is also pointed out that by reducing the systematic uncertainties of both T2K-II and NO$\nu$A to a level of  2\%, the sensitivity to CP-violation will significantly increase with a discovery possibility at 5$\sigma$ C.L. significance for a particular range of true \(\delta_{CP}\).

INVISIBLE AXIONS AND LIGHT NEUTRINOS—ARE THEY CONNECTED?

1986 ◽  
Vol 01 (09) ◽  
pp. 541-552 ◽  
Author(s):  
P. LANGACKER ◽  
R.D. PECCEI ◽  
T. YANAGIDA
Keyword(s):  
Symmetry Breaking ◽  
Solar Neutrino ◽  
Lepton Number ◽  
Solar Neutrino Problem ◽  
Spontaneous Breakdown ◽  
Breaking Parameter ◽  
Invisible Axion ◽  
The Universe ◽  
The Invisible

Physical arguments involving the solar neutrino problem are given which connect the scale of U (1)PQ breakdown with that of the spontaneous breakdown of lepton number. In the simplest model, the Majoron transmutes itself into the invisible axion as a soft symmetry breaking parameter is turned on. Some consequences of this idea are discussed. These include a suggestion that the origin of the baryon symmetry of the Universe is connected with an induced lepton number asymmetry produced at temperatures of order VPQ and the possibility that νμ→ντ oscillations may be observable at accelerators.

scholarly journals The Dirac Sea, T and C Symmetry Breaking, and the Spinor Vacuum of the Universe

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 124
Author(s):  
Vadim Monakhov
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Symmetry Breaking ◽  
Momentum Space ◽  
Quantum Field ◽  
Conjugation Operator ◽  
Dirac Sea ◽  
Canonical Anticommutation Relations ◽  
The Universe ◽  
Dirac Conjugation

We have developed a quantum field theory of spinors based on the algebra of canonical anticommutation relations (CAR algebra) of Grassmann densities in the momentum space. We have proven the existence of two spinor vacua. Operators C and T transform the normal vacuum into an alternative one, which leads to the breaking of the C and T symmetries. The CPT is the real structure operator; it preserves the normal vacuum. We have proven that, in the theory of the Dirac Sea, the formula for the charge conjugation operator must contain an additional generalized Dirac conjugation operator.

scholarly journals Primordial monopoles and strings, inflation, and gravity waves

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Joydeep Chakrabortty ◽  
George Lazarides ◽  
Rinku Maji ◽  
Qaisar Shafi
Keyword(s):  
Symmetry Breaking ◽  
Gravity Waves ◽  
Cosmic Strings ◽  
Wave Spectrum ◽  
Gauge Coupling ◽  
String Tension ◽  
Magnetic Monopoles ◽  
Intermediate Scale ◽  
Tension Parameter ◽  
The Universe

Abstract We consider magnetic monopoles and strings that appear in non-supersymmetric SO(10) and E6 grand unified models paying attention to gauge coupling unification and proton decay in a variety of symmetry breaking schemes. The dimensionless string tension parameter Gμ spans the range 10−6− 10−30, where G is Newton’s constant and μ is the string tension. We show how intermediate scale monopoles with mass ∼ 1013− 1014 GeV and flux ≲ 2.8 × 10−16 cm−2s−1sr−1, and cosmic strings with Gμ ∼ 10−11− 10−10 survive inflation and are present in the universe at an observable level. We estimate the gravity wave spectrum emitted from cosmic strings taking into account inflation driven by a Coleman-Weinberg potential. The tensor-to-scalar ratio r lies between 0.06 and 0.003 depending on the details of the inflationary scenario.

Sign in / Sign up

Export Citation Format

Share Document