scholarly journals KNOTTED STRINGS AND LEPTONIC FLAVOR STRUCTURE

2012 ◽  
Vol 27 (38) ◽  
pp. 1250224 ◽  
Author(s):  
T. W. KEPHART ◽  
P. LESER ◽  
H. PÄS
Keyword(s):  
String Theory ◽  
Mass Spectra ◽  
Theory Model ◽  
Flavor Symmetry ◽  
Type I ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Flavor Structure ◽  
Knots And Links

We propose a third idea for the explanation of the leptonic flavor structure in addition to the prominent approaches based on flavor symmetry and anarchy. Typical flavor patterns can be modeled by using mass spectra obtained from the discrete lengths spectrum of tight knots and links. We assume that a string theory model exists in which this idea can be incorporated via the Majorana mass structure of a type I seesaw model. It is shown by a scan over the parameter space that such a model is able to provide an excellent fit to current neutrino data and that it predicts a normal neutrino mass hierarchy as well as a small mixing angle θ13. Startlingly, such scenarios could be related to the dimensionality of spacetime via an anthropic argument.

scholarly journals PREDICTIVE MODEL OF INVERTED NEUTRINO MASS HIERARCHY AND RESONANT LEPTOGENESIS

2008 ◽  
Vol 23 (11) ◽  
pp. 1679-1696 ◽  
Author(s):  
K. S. BABU ◽  
ABDEL G. BACHRI ◽  
ZURAB TAVARTKILADZE
Keyword(s):  
Neutrino Mass ◽  
Flavor Symmetry ◽  
Mass Hierarchy ◽  
Β Decay ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Double Β Decay ◽  
The Masses ◽  
The Universe ◽  
Charged Lepton Sector

We present a new realization of inverted neutrino mass hierarchy based on [Formula: see text] flavor symmetry. In this scenario, the deviation of the solar oscillation angle from π/4 is correlated with the value of θ13, as they are both induced by a common mixing angle in the charged lepton sector. We find several interesting predictions: θ13≥ 0.13, sin2θ12≥ 0.31, sin2θ23≃ 0.5 and 0 ≤ cos δ ≤ 0.7 for the neutrino oscillation parameters and 0.01 ≲ mββ≲ 0.02 eV for the effective neutrino mass in neutrino-less double β-decay. We show that our scenario can also explain naturally the observed baryon asymmetry of the universe via resonant leptogenesis. The masses of the decaying right-handed neutrinos can be in the range (103–107) GeV, which would avoid the generic gravitino problem of supersymmetric models.

scholarly journals Lepton masses and mixings in a T′ flavored 3-3-1 model with type I and type II seesaw mechanisms

2019 ◽  
Vol 34 (01) ◽  
pp. 1950005 ◽  
Author(s):  
V. V. Vien ◽  
H. N. Long ◽  
A. E. Cárcamo Hernández
Keyword(s):  
Neutrino Mass ◽  
Mass Parameter ◽  
Majorana Neutrino ◽  
Type I ◽  
Mass Hierarchy ◽  
Type Ii ◽  
Lepton Sector ◽  
Neutrino Mass Hierarchy ◽  
Majorana Neutrinos ◽  
Majorana Neutrino Mass

We propose a renormalizable T′ flavor model based on the [Formula: see text] gauge symmetry, consistent with the observed pattern of lepton masses and mixings. The small masses of the light active neutrinos are produced from an interplay of type I and type II seesaw mechanisms, which are induced by three heavy right-handed Majorana neutrinos and three [Formula: see text] scalar antisextets, respectively. Our model is only viable for the scenario of normal neutrino mass hierarchy, where the obtained physical observables of the lepton sector are highly consistent with the current neutrino oscillation experimental data. In addition, our model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] eV, a Jarlskog invariant of the order of [Formula: see text] and a leptonic Dirac CP violating phase of [Formula: see text], which is inside the [Formula: see text] experimentally allowed range.

scholarly journals Flavored leptogenesis and neutrino mass with A4 symmetry

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Arghyajit Datta ◽  
Biswajit Karmakar ◽  
Arunansu Sil
Keyword(s):  
Renormalization Group ◽  
Neutrino Masses ◽  
Symmetric Model ◽  
Type I ◽  
Normal Hierarchy ◽  
High Scale ◽  
Mixing Angle ◽  
Flavor Structure ◽  
Interesting Correlation ◽  
The Right

Abstract We propose a minimal A4 flavor symmetric model, assisted by Z2× Z3 symmetry, which can naturally takes care of the appropriate lepton mixing and neutrino masses via Type-I seesaw. It turns out that the framework, originated due to a specific flavor structure, favors the normal hierarchy of light neutrinos and simultaneously narrows down the range of Dirac CP violating phase. It predicts an interesting correlation between the atmospheric mixing angle and the Dirac CP phase too. While the flavor structure indicates an exact degeneracy of the right-handed neutrino masses, renormalization group running of the same from a high scale is shown to make it quasi-degenerate and a successful flavor leptogenesis takes place within the allowed parameter space obtained from neutrino phenomenology.

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.

scholarly journals On resolving the dark LMA solution at neutrino oscillation experiments

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Sandhya Choubey ◽  
Dipyaman Pramanik
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Double Beta Decay ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Long Baseline ◽  
Combine Information ◽  
Oscillation Experiment

Abstract In presence of non standard interactions (NSI), the solar neutrino data is consistent with two solutions, one close to the standard LMA solution with sin2θ12 ≃ 0.31 and another with $$ {\sin}^2{\theta}_{12}^D\simeq 0.69\left(=1-{\sin}^2{\theta}_{12}\right) $$ sin 2 θ 12 D ≃ 0.69 = 1 − sin 2 θ 12 . The latter has been called the Dark LMA (DLMA) solution in the literature and essentially brings an octant degeneracy in the measurement of the mixing angle θ12. This θ12 octant degeneracy is hard to resolve via oscillations because of the existence of the so-called “generalised mass hierarchy degeneracy” of the neutrino mass matrix in presence of NSI. One might think that if the mass hierarchy is independently determined in a non-oscillation experiment such as neutrino-less double beta decay, one might be able to break the θ12 octant degeneracy. In this paper we study this in detail in the context of long-baseline experiments (Pμμ channel) as well as reactor experiments (Pee channel) and show that if we combine information from both long-baseline and reactor experiments we can find the correct octant and hence value of θ12. We elaborate the reasons for it and study the prospects of determining the θ12 octant using T2HK, DUNE and JUNO experiments. Of course, one would need information on the neutrino mass hierarchy as well.

scholarly journals Deviations from tribimaximal neutrino mixing using a model with Δ(27) symmetry

2014 ◽  
Vol 29 (18) ◽  
pp. 1450095 ◽  
Author(s):  
P. F. Harrison ◽  
R. Krishnan ◽  
W. G. Scott
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Diagonal Form ◽  
Mass Hierarchy ◽  
Neutrino Mixing ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Mass Matrices ◽  
Mixing Patterns ◽  
Reactor Mixing

We present a model of neutrino mixing based on the flavor group Δ(27) in order to account for the observation of a nonzero reactor mixing angle (θ13). The model provides a common flavor structure for the charged-lepton and the neutrino sectors, giving their mass matrices a "circulant-plus-diagonal" form. Mass matrices of this form readily lead to mixing patterns with realistic deviations from tribimaximal mixing, including nonzero θ13. With the parameters constrained by existing measurements, our model predicts an inverted neutrino mass hierarchy. We obtain two distinct sets of solutions in which the atmospheric mixing angle lies in the first and the second octants. The first (second) octant solution predicts the lightest neutrino mass, m3~29 meV (m3~65 meV ) and the CP phase, [Formula: see text], offering the possibility of large observable CP violating effects in future experiments.

Ramifications of texture one-zero neutrino mass model in coherence with the latest neutrino data

2020 ◽  
Vol 35 (20) ◽  
pp. 2050165 ◽  
Author(s):  
Surender Verma ◽  
Monal Kashav
Keyword(s):  
Abelian Group ◽  
Cp Violation ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Type I ◽  
Mass Hierarchy ◽  
Mass Model ◽  
Neutrino Mass Hierarchy ◽  
Neutrino Mass Models

We have investigated the phenomenological implications of texture one-zero neutrino mass matrix under the lamp post of the latest data on neutrino mass and mixings. In particular, we have obtained the predictions of the model for, yet unknown observables like neutrino mass hierarchy, [Formula: see text]-octant and CP violation. Out of the six texture one-zero neutrino mass models, [Formula: see text], [Formula: see text] and [Formula: see text] are found to be necessarily CP violating. [Formula: see text] can be above or below maximality except for the texture [Formula: see text] (with NH), wherein [Formula: see text] at [Formula: see text]. Also, we have proposed a flavor model based on the non-Abelian group [Formula: see text] within the paradigm of type-I+II seesaw framework, wherein such textures can be realized.

scholarly journals Physics Potential of Long-Baseline Experiments

2014 ◽  
Vol 2014 ◽  
pp. 1-29 ◽  
Author(s):  
Sanjib Kumar Agarwalla
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
New Physics ◽  
Mass Hierarchy ◽  
Neutrino Mixing ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Long Baseline ◽  
Physics Potential ◽  
Flavor Oscillation

The discovery of neutrino mixing and oscillations over the past decade provides firm evidence for new physics beyond the Standard Model. Recently,θ13has been determined to be moderately large, quite close to its previous upper bound. This represents a significant milestone in establishing the three-flavor oscillation picture of neutrinos. It has opened up exciting prospects for current and future long-baseline neutrino oscillation experiments towards addressing the remaining fundamental questions, in particular the type of the neutrino mass hierarchy and the possible presence of a CP-violating phase. Another recent and crucial development is the indication of non-maximal 2-3 mixing angle, causing the octant ambiguity ofθ23. In this paper, I will review the phenomenology of long-baseline neutrino oscillations with a special emphasis on sub-leading three-flavor effects, which will play a crucial role in resolving these unknowns. First, I will give a brief description of neutrino oscillation phenomenon. Then, I will discuss our present global understanding of the neutrino mass-mixing parameters and will identify the major unknowns in this sector. After that, I will present the physics reach of current generation long-baseline experiments. Finally, I will conclude with a discussion on the physics capabilities of accelerator-driven possible future long-baseline precision oscillation facilities.

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