scholarly journals Neutrinos and the structure of space-time

2014 ◽  
Vol 12 (2) ◽  
pp. 179-188
Author(s):  
Argyris Nicolaidis
Keyword(s):  
Neutrino Oscillations ◽  
Sterile Neutrino ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Mixing Angles ◽  
Dirac Type ◽  
Majorana Mass ◽  
Left Handed ◽  
Proposed Model ◽  
Type Coupling

The phenomenon of neutrino oscillations is studied usually as a mixing between the flavor neutrinos and the neutrinos having a definite mass. The mixing angles and the mass eigenvalues are treated independently in order to accommodate the experimental data. We suggest that neutrino oscillations are connected to the structure of spacetime. We expand on a recently proposed model, where two ?mirror? branes coexist. One brane hosts left-handed particles (our brane), while the other brane hosts right-handed particles. Majorana-type couplings mixes neutrinos in an individual brane, while Dirac-type couplings mixes neutrinos across the brares. We first focus our attention in a single brane. The mass matrix, determined by the Majorana mass, leads to mass eigenstates and further to mixing angles identical to the mixing angles proposed by the tri-bimaximal mixing. When we include the Dirac-type coupling, connecting the two branes, we obtain a definite prediction for the transition to a sterile neutrino (righthanded neutrino). With mL (mR) the Majorana mass for the left (right) brane, we are able to explain the solar and the atmospheric neutrino data with mL = 2mR and mR = 10-2 eV.

scholarly journals NEUTRINO OSCILLATIONS AND THE EXACT PARITY MODEL

1994 ◽  
Vol 09 (02) ◽  
pp. 169-179 ◽  
Author(s):  
R. FOOT
Keyword(s):  
Neutrino Mass ◽  
General Result ◽  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Solar Neutrinos ◽  
Specific Model ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Significant Deficit

We re-examine neutrino oscillations in exact parity models. Previously it was shown in a specific model that large neutrino mixing angles result. We show here that this is a general result of neutrino mixing in exact parity models provided that the neutrino mass matrix is real. In this case, the effects of neutrino mixing in exact parity models is such that the probability of a given weak eigenstate remaining in that eigenstate averages to less than half when averaged over many oscillations. This result is interesting in view of the accumulating evidence for a significant deficit in the number of solar neutrinos. It may also be of relevance to the atmospheric neutrino anomaly.

WHAT DOES μ - τ SYMMETRY IMPLY ABOUT LEPTONIC CP VIOLATION?

2007 ◽  
Vol 16 (05) ◽  
pp. 1373-1381 ◽  
Author(s):  
TEPPEI BABA
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Symmetry Breaking ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Difference ◽  
Atmospheric Neutrino ◽  
Symmetric Part ◽  
Neutrino Mixing ◽  
Mixing Angles

The μ - τ symmetry can reproduce the consistent results with experimental data of θ13, and θ23 (θ13, and θ23 respectively denote the νe - ντ, and νμ - ντ, mixing angles). However, we can not address the issue of the leptonic CP violation in μ - τ symmetric models. So we add the μ - τ symmetry breaking part to include the CP violation. We characterize leptonic CP violation in terms of three phases, where one is conventional phase δ and others are additional phases ρ and γ. These δ, ρ and γ are, respectively, the phases of νe - ντ, νe - νμ and νμ - ντ mixings. The ρ and γ are redundant but the effect of ρ remains in the leptonic CP violation which is characterized by δ + ρ. The δ arises from the μ - τ symmetry breaking part of the Meμ and Meτ while ρ arises from of μ - τ symmetric part of the Meμ and Meτ, where Mij stands for ij (i,j = e,μ,τ) element of M(= [Formula: see text] for Mν being a flavor neutrino mass matrix). Moreover, θ23 can be exactly estimated to be: [Formula: see text] ( sin θ ∝ sin θ13 cos (δ + ρ)[Formula: see text], sin ϕ ∝ Mμμ - Mττ, where [Formula: see text] is the solar neutrino mass difference squared). The conditions of maximal atmospheric neutrino mixing are given by [Formula: see text] and Mμμ = Mττ,which indicate maximal Dirac CP violation.

scholarly journals $$3+1$$ active–sterile neutrino mixing in $$B-L$$ model with $$S_{3}{\times Z_4\times Z_2}$$ symmetry for normal neutrino mass ordering

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
V. V. Vien
Keyword(s):  
Neutrino Mass ◽  
Sterile Neutrino ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Yukawa Interaction ◽  
Neutrino Mixing ◽  
Normal Ordering ◽  
Mixing Angles ◽  
Active Mixing ◽  
Best Fit

AbstractWe propose a non-renormalizable $$B-L$$ B - L model with $$S_{3}{\times Z_4\times Z_2}$$ S 3 × Z 4 × Z 2 symmetry which successfully accommodates the current active–sterile neutrino mixing in $$3+1$$ 3 + 1 scheme. The $$S_3$$ S 3 flavor symmetry is supplemented by $$Z_4\otimes Z_2$$ Z 4 ⊗ Z 2 symmetry to consolidate the Yukawa interaction of the model. The presence of $$S_3\otimes Z_4\otimes Z_2$$ S 3 ⊗ Z 4 ⊗ Z 2 flavour symmetry plays an important role in generating the desired structure of the neutrino mass matrix. The model can reproduce the recent observed active-neutrino neutrino oscillation data for normal ordering in which two sterile–active mixing angles $$\theta _{14, 24}$$ θ 14 , 24 get the best-fit values and the obtained values of $$\theta _{34}, \delta _{14}, \delta _{14}$$ θ 34 , δ 14 , δ 14 , the sum of neutrino mass and the effective neutrino masses are within their currently allowed ranges.

scholarly journals INVERTED NEUTRINO MASS HIERARCHIES FROM U(1) SYMMETRIES

2006 ◽  
Vol 21 (26) ◽  
pp. 5187-5204 ◽  
Author(s):  
G. K. LEONTARIS ◽  
A. PSALLIDAS ◽  
N. D. VLACHOS
Keyword(s):  
Neutrino Mass ◽  
Atmospheric Neutrino ◽  
Vacuum Expectation ◽  
Family Symmetry ◽  
Mixing Angles ◽  
Lepton Flavor ◽  
Left Handed ◽  
Energy Models ◽  
Mass Matrices ◽  
Higgs Fields

Motivated by effective low energy models of string origin, we discuss the neutrino masses and mixing within the context of the Minimal Supersymmetric Standard Model supplemented by a U(1) anomalous family symmetry and additional Higgs singlet fields charged under this extra U(1). In particular, we interpret the solar and atmospheric neutrino data assuming that there are only three left-handed neutrinos which acquire Majorana masses via a lepton number violating dimension-five operator. We derive the general form of the charged lepton and neutrino mass matrices when two different pairs of singlet Higgs fields develop nonzero vacuum expectation values and show how the resulting neutrino textures are related to approximate lepton flavor symmetries. We perform a numerical analysis for one particular case and obtain solutions for masses and mixing angles, consistent with experimental data.

scholarly journals CAN THE SUPER-KAMIOKANDE ATMOSPHERIC DATA PREDICT THE SOLAR NEUTRINO DEFICIT?

1999 ◽  
Vol 14 (10n11) ◽  
pp. 689-700 ◽  
Author(s):  
ION STANCU
Keyword(s):  
Solar Neutrino ◽  
Neutrino Oscillations ◽  
Atmospheric Neutrino ◽  
Neutrino Flux ◽  
Experimental Results ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Atmospheric Data ◽  
Mixing Matrix ◽  
Good Agreement

In this letter we show that the evidence for neutrino oscillations from the super-Kamiokande atmospheric neutrino data fully determines the 3×3 neutrino-oscillations mixing matrix and predicts an energy-independent solar neutrino deficit at the level of 45%. This corresponds to a ratio of measured to predicted neutrino flux of [Formula: see text], in good agreement with the experimental results. We achieve this result within the framework of a minimal, three-generation neutrino mixing, with mass squared differences of ΔM2≃0.45 eV 2 and [Formula: see text]. The mixing matrix derived here is characterized by the mixing angles θ=35.1°, β=5.5° and ψ=23.3°, and a vanishing CP-violating phase, δ=0.

scholarly journals PHENOMENOLOGY OF "BIMAXIMAL + DEMOCRATIC" TYPE NEUTRINO MASS MATRIX

2006 ◽  
Vol 21 (13) ◽  
pp. 1067-1073 ◽  
Author(s):  
AMBAR GHOSAL ◽  
DEBASISH MAJUMDAR
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mass Matrix ◽  
Experimental Results ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Mixing Angles ◽  
The Masses

We demonstrate that "Bimaximal + Democratic" type neutrino mass matrix can accommodate the deviation of θ⊙ from its maximal value along with the other present-day neutrino experimental results, namely, atmospheric, CHOOZ, neutrinoless double beta decay (ββ0ν) and result obtained from WMAP experiment. We define a function χp in terms of solar and atmospheric neutrino mass squared differences and solar neutrino mixing angle (obtained from different experiments and our proposed texture). The masses and mixing angles are expressed in terms of three parameters in our proposed texture. The allowed region of the texture parameters is obtained through minimization of the above function. The proposed texture crucially depends on the value of the experimental results of ββ0ν experiment among all other above-mentioned experiments. If, in future, ββ0ν experiments, namely, MOON, EXO, GENIUS shift the lower bound on 〈mee〉 at the higher side by one order, the present texture will be ruled out.

scholarly journals SHORT-BASELINE ACTIVE-STERILE NEUTRINO OSCILLATIONS?

2007 ◽  
Vol 22 (33) ◽  
pp. 2499-2509 ◽  
Author(s):  
CARLO GIUNTI ◽  
MARCO LAVEDER
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Oscillations ◽  
Sterile Neutrino ◽  
Mass Difference ◽  
Atmospheric Neutrino ◽  
Radioactive Source ◽  
Short Baseline

We suggest the possibility that the anomalies observed in the LSND experiment and the Gallium radioactive source experiments may be due to neutrino oscillations generated by a large squared-mass difference of about 20–30 eV2. We consider the simplest 3+1 four-neutrino scheme that can accommodate also the observed solar and atmospheric neutrino oscillations. We show that, in this framework, the disappearance of [Formula: see text] and [Formula: see text] in short-baseline neutrino oscillation experiments is mainly due to active-sterile transitions. The implications of the first MiniBooNE results, appeared after the completion of this paper, are discussed in an addendum.

scholarly journals SO(10)-INSPIRED SEESAW MECHANISM

2001 ◽  
Vol 16 (04) ◽  
pp. 609-623 ◽  
Author(s):  
MARIO ABUD ◽  
FRANCO BUCCELLA
Keyword(s):  
Experimental Data ◽  
Solar Neutrino ◽  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Matrix Elements ◽  
Seesaw Mechanism ◽  
Solar Neutrino Problem ◽  
Majorana Mass ◽  
The Matrix

We determine the νR Majorana mass matrix from the experimental data on neutrino oscillations in the framework of a see-saw SO(10) model, where we impose the condition (MR)33=0 to avoid too large fine-tunings in the see-saw formula. We find a class of solutions with the two lowest neutrino masses almost degenerate and the scale of the matrix elements of MR in the range 1011–1012 GeV in agreement with Pati–Salam intermediate symmetry. We find also solutions with smaller neutrino masses, for which the scale of MR depends on the solution to the "solar neutrino problem" and on the value of the component of νe along the highest mass eigenstate, Ue3.

scholarly journals MASS AND MIXING OF FERMIONS FROM A ROTATING MASS MATRIX

2003 ◽  
Vol 18 (12) ◽  
pp. 807-815
Author(s):  
SHEUNG TSUN TSOU ◽  
JONATHAN S. PALMER
Keyword(s):  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Mass Scale ◽  
Energy Scale ◽  
Ckm Matrix ◽  
Mass Ratios ◽  
Existing Data

We summarize the results showing that all existing data on mixing between up and down fermion states (i.e. CKM matrix and neutrino oscillations) and on the hierarchical quark and lepton mass ratios between generations are consistent with the two phenomena being both consequences of a mass matrix rotating in generation space with changing energy scale. Thus the rotation of the mass matrix can be traced over some 14 orders of magnitude in energy from the mass scale of the t-quark at 175 GeV to below that of the atmospheric neutrino at 0.05 eV.

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