scholarly journals TEXTURE ZEROS FOR DIRAC NEUTRINOS AND CURRENT EXPERIMENTAL TESTS

2013 ◽  
Vol 28 (12) ◽  
pp. 1350040 ◽  
Author(s):  
XUE-WEN LIU ◽  
SHUN ZHOU
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Experimental Tests ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Dirac Particles ◽  
Texture Zero ◽  
Reactor Neutrino ◽  
The Stability ◽  
Neutrino Experiments

The Daya Bay and RENO reactor neutrino experiments have revealed that the smallest neutrino mixing angle is in fact relatively large, i.e. θ13 ≈9°. Motivated by this exciting progress, we perform a systematic study of the neutrino mass matrix Mν with one or two texture zeros, in the assumption that neutrinos are Dirac particles. Among 15 possible patterns with two texture zeros, only three turn out to be favored by current neutrino oscillation data at the 3σ level. Although all the six patterns with one texture zero are compatible with the experimental data at the 3σ level, the parameter space of each pattern is strictly constrained. Phenomenological implications of Mν on the leptonic CP violation and neutrino mass spectrum are explored, and the stability of texture zeros against the radiative corrections is also discussed.

scholarly journals Investigating the Hybrid Textures of Neutrino Mass Matrix for Near Maximal Atmospheric Neutrino Mixing

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Madan Singh
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Zero Element ◽  
Majorana Neutrino ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
The Comparative Study ◽  
Reactor Mixing ◽  
Majorana Neutrino Mass

We have studied that the implication of a large value of the effective Majorana neutrino mass in case of neutrino mass matrices has either two equal elements and one zero element (popularly known as hybrid texture) or two equal cofactors and one zero minor (popularly known as inverse hybrid texture) in the flavor basis. In each of these cases, four out of sixty phenomenologically possible patterns predict near maximal atmospheric neutrino mixing angle in the limit of large effective Majorana neutrino mass. This feature remains irrespective of the experimental data on solar and reactor mixing angles. In addition, we have also performed the comparative study of all the viable cases of hybrid and inverse hybrid textures at 3σ CL.

scholarly journals TEXTURE-ZERO MODEL FOR THE LEPTON MASS MATRICES

2012 ◽  
Vol 27 (28) ◽  
pp. 1250159 ◽  
Author(s):  
P. M. FERREIRA ◽  
L. LAVOURA
Keyword(s):  
Mass Spectrum ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Type I ◽  
Mixing Angle ◽  
Mass Matrices ◽  
Neutrino Mass Spectrum ◽  
Texture Zero ◽  
Vanishing Elements ◽  
Reactor Mixing

We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and Meμ = 0 (M is the effective light-neutrino Majorana mass matrix). We show that these predictions agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if m3 = 0, provided the Dirac phase δ is very close to maximal (±π/ 2). In the case of a normal neutrino mass spectrum, i.e. when m1 = 0, the agreement of our model with the data is imperfect — the reactor mixing angle θ13 is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.

scholarly journals CHARGED LEPTON CORRECTION TO TRI-BIMAXIMAL LEPTON MIXING AND ITS IMPLICATIONS TO NEUTRINO PHENOMENOLOGY

2013 ◽  
Vol 28 (31) ◽  
pp. 1350131 ◽  
Author(s):  
SRINU GOLLU ◽  
K. N. DEEPTHI ◽  
R. MOHANTA
Keyword(s):  
Charged Lepton ◽  
Daya Bay ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Quark Sector ◽  
Mass Matrices ◽  
Reactor Neutrino ◽  
Mixing Matrix ◽  
Neutrino Experiments ◽  
Reactor Mixing

The recent results from Daya Bay and RENO reactor neutrino experiments have firmly established that the smallest reactor mixing angle θ13 is nonvanishing at the 5 σ level, with a relatively large value, i.e. θ13 ≈ 9°. Using the fact that the neutrino mixing matrix can be represented as [Formula: see text], where Ul and Uν result from the diagonalization of the charged lepton and neutrino mass matrices and Pν is a diagonal matrix containing the Majorana phases and assuming the tri-bimaximal (TBM) form for Uν, we investigate the possibility of accounting for the large reactor mixing angle due to the corrections of the charged lepton mixing matrix. The form of Ul is assumed to be that of CKM mixing matrix of the quark sector. We find that with this modification it is possible to accommodate the large observed reactor mixing angle θ13. We also study the implications of such corrections on the other phenomenological observables.

scholarly journals REVIEW OF REACTOR NEUTRINO OSCILLATION EXPERIMENTS

2012 ◽  
Vol 27 (08) ◽  
pp. 1230010 ◽  
Author(s):  
C. MARIANI
Keyword(s):  
Neutrino Physics ◽  
Neutrino Oscillation ◽  
Current Status ◽  
Daya Bay ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Double Chooz ◽  
Reactor Neutrino ◽  
Neutrino Experiments ◽  
Near Future

In this document we will review the current status of reactor neutrino oscillation experiments and present their physics potentials for measuring the θ13 neutrino mixing angle. The neutrino mixing angle θ13 is currently a high-priority topic in the field of neutrino physics. There are currently three different reactor neutrino experiments, DOUBLE CHOOZ, DAYA BAY and RENO and a few accelerator neutrino experiments searching for neutrino oscillations induced by this angle. A description of the reactor experiments searching for a nonzero value of θ13 is given, along with a discussion of the sensitivities that these experiments can reach in the near future.

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 Energy non-linearity studies at Daya Bay

2014 ◽  
Vol 31 ◽  
pp. 1460312 ◽  
Author(s):  
Masheng Yang ◽  
Yaping Cheng ◽  
Keyword(s):  
Energy Spectrum ◽  
Neutrino Mass ◽  
Shape Analysis ◽  
Mass Splitting ◽  
Neutrino Energy ◽  
Daya Bay ◽  
Neutrino Experiment ◽  
Neutrino Mixing ◽  
Mixing Angle ◽  
Reactor Neutrino

The Daya Bay Reactor Neutrino Experiment has measured a non-zero value of the neutrino mixing angle θ13 with a significance of 7.7 standard deviations by a rate-only analysis.1 The distortion of neutrino energy spectrum carries additional oscillation information and can improve the sensitivity of θ13 as well as measure neutrino mass splitting [Formula: see text]. A rate plus shape analysis is performed and the results have been published.2 Understanding detector energy non-linearity response is crucial for the rate plus shape analysis. In this contribution, we present a brief description of energy non-linearity studies at Daya Bay.

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 CORRECTIONS TO TRIBIMAXIMAL MIXING FROM NONDEGENERATE PHASES

2010 ◽  
Vol 25 (01) ◽  
pp. 63-78 ◽  
Author(s):  
Y. F. LI ◽  
Q. Y. LIU
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Zero Order ◽  
Leading Order ◽  
Small Deviations ◽  
Mixing Angle ◽  
Neutrino Mass Spectrum ◽  
Small Phase ◽  
The Stability ◽  
The Right

We propose a seesaw scenario that possible corrections to the tribimaximal pattern of lepton mixing are due to the small phase splitting of the right-handed neutrino mass matrix. We show that the small deviations can be expressed analytically in terms of two splitting parameters (δ1 and δ2) in the leading order. The solar mixing angle θ12 favors a relatively smaller value compared to zero order value (35.3°), and the Dirac type CP phase δ chooses a nearly maximal one. The two Majorana type CP phases ρ and σ turn out to be a nearly linear dependence. Also a normal hierarchy neutrino mass spectrum is favored due to the stability of perturbation calculations.

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.

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