Neutrino Masses and Mixings

2019 ◽  
pp. 313-326
Author(s):  
Michael E. Peskin
Keyword(s):  
Experimental Determination ◽  
Neutrino Mass ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Neutrino Flavor ◽  
Flavor Mixing ◽  
Pmns Matrix ◽  
The Masses ◽  
Neutrino Masses And Mixings

This chapter discusses the search for and eventual discovery of the masses of neutrinos. It explains that observability of neutrino mass depends on neutrino flavor mixing. It introduces the PMNS matrix describing neutrino mixing and describes the experimental determination of the parameters of this matrix.

scholarly journals NEUTRINO OSCILLATIONS AND LEPTON FLAVOR MIXING

2001 ◽  
Vol 16 (33) ◽  
pp. 2169-2175 ◽  
Author(s):  
KYUNGSIK KANG ◽  
SIN KYU KANG ◽  
C. S. KIM ◽  
SUN MYONG KIM
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Input Constraints ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Invariance Violation ◽  
The Family ◽  
Flavor Mixing ◽  
Mixing Matrix

In view of the recent announcement on nonzero neutrino mass from Super-Kamiokande experiment, it would be very timely to investigate all the possible scenarios on masses and mixings of light neutrinos. Recently suggested mass matrix texture for the quark CKM mixing, which can be originated from the family permutation symmetry and its suitable breakings, is assumed for the neutrino mass matrix and determined by the four combinations of solar, atmospheric and LSND neutrino data and cosmological hot dark matter bound as input constraints. The charged-lepton mass matrix is assumed to be diagonal so that the neutrino mixing matrix can be identified directly as the lepton flavor mixing matrix and no CP invariance violation originates from the leptonic sector. The results favor hierarchical patterns for the neutrino masses, which follow from the case when the solar-atmospheric data is used.

EFFECTS OF CP VIOLATING PHASES ON THE INVERSE NEUTRINOLESS DOUBLE BETA SCATTERING e-e- → W-W-

2012 ◽  
Vol 27 (14) ◽  
pp. 1250053
Author(s):  
S. AKASLAN ◽  
A. U. YILMAZER
Keyword(s):  
Double Beta Decay ◽  
Neutrino Masses ◽  
Matrix Elements ◽  
Neutrino Mixing ◽  
Open Problems ◽  
Helicity Amplitudes ◽  
Mixing Matrix ◽  
The Masses ◽  
Positive Results

The most important open problems of the today's neutrino physics are the absolute values of the neutrino masses, the determination of the Dirac or the Majorana character and better measurements of the mixing matrix elements. Results of the neutrino oscillations experiments strongly confirm that the neutrinos have nonzero masses. Experiments give information about the differences between the squares of the masses but not any knowledge on their absolute values. Similarly neutrino oscillation phenomena does not help us to understand their Dirac or Majorana character. One of the processes that could clarify this important point is the double beta decay and the search is still going on but not yielded any positive results due to the big experimental difficulties. Also the inverse of this decay, e-e- → W-W- is another process that could be tested at the accelerators. This process is possible only if the neutrinos have masses and they are Majorana particles. Since neutrinos could have very tiny masses and the cross section of the above process is proportional to the square of the effective neutrino mass it is an extremely rare process. Also it violates total lepton number by two units, Δ = 2. In the literature the inverse neutrinoless double beta scattering have been extensively studied, in this article we obtain the relevant helicity amplitudes, investigate the effects of the neutrino mixing matrix elements, especially the roles of the CP violating phases and the possible CP asymmetries.

OVERVIEW OF SUSY GUT MODELS OF NEUTRINO MIXING

2003 ◽  
Vol 18 (22) ◽  
pp. 3971-3979 ◽  
Author(s):  
S.M. BARR
Keyword(s):  
Grand Unification ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Neutrino Masses And Mixings

A brief review is given of some ideas for explaining neutrino masses and mixings within the context of supersymmetric grand unification. Emphasis is put on so-called lopsided models.

scholarly journals NEUTRINO MASSES, LEPTON FLAVOR MIXING AND LEPTOGENESIS IN THE MINIMAL SEESAW MODEL

2007 ◽  
Vol 16 (01) ◽  
pp. 1-50 ◽  
Author(s):  
WAN-LEI GUO ◽  
ZHI-ZHONG XING ◽  
SHUN ZHOU
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Seesaw Model ◽  
Flavor Mixing ◽  
Majorana Neutrinos

We present a review of neutrino phenomenology in the minimal seesaw model (MSM), an economical and intriguing extension of the Standard Model with only two heavy right-handed Majorana neutrinos. Given current neutrino oscillation data, the MSM can predict the neutrino mass spectrum and constrain the effective masses of the tritium beta decay and the neutrinoless double-beta decay. We outline five distinct schemes to parameterize the neutrino Yukawa-coupling matrix of the MSM. The lepton flavor mixing and baryogenesis via leptogenesis are investigated in some detail by taking account of possible texture zeros of the Dirac neutrino mass matrix. We derive an upper bound on the CP-violating asymmetry in the decay of the lighter right-handed Majorana neutrino. The effects of the renormalization-group evolution on the neutrino mixing parameters are analyzed, and the correlation between the CP-violating phenomena at low and high energies is highlighted. We show that the observed matter-antimatter asymmetry of the Universe can naturally be interpreted through the resonant leptogenesis mechanism at the TeV scale. The lepton-flavor-violating rare decays, such as μ→e+γ, are also discussed in the supersymmetric extension of the MSM.

Texture zero mass matrices and flavor mixing of quarks and leptons

2015 ◽  
Vol 30 (28) ◽  
pp. 1550138 ◽  
Author(s):  
Harald Fritzsch
Keyword(s):  
Experimental Data ◽  
Neutrino Masses ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Zero Mass ◽  
Fermion Masses ◽  
Mass Matrices ◽  
Flavor Mixing ◽  
Texture Zero ◽  
The Masses

We discuss mass matrices with four texture zeros for the quarks and leptons. The three mixing angles for the quarks and leptons are functions of the fermion masses. The results agree with the experimental data. The ratio of the masses of the first two neutrinos is given by the solar mixing angle. The neutrino masses are calculated: [Formula: see text], [Formula: see text] and [Formula: see text].

Vanishing effective Majorana neutrino mass and light sterile neutrinos

2016 ◽  
Vol 31 (06) ◽  
pp. 1650040 ◽  
Author(s):  
Surender Verma
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Majorana Neutrino ◽  
Recent Measurement ◽  
Neutrino Masses ◽  
Sterile Neutrinos ◽  
Majorana Mass ◽  
Scatter Plots ◽  
Majorana Neutrino Mass ◽  
Neutrino Masses And Mixings

We examine the possibility of vanishing effective Majorana mass [Formula: see text] in the presence of one or two sterile neutrinos taking into account the recent data on neutrino masses and mixings, particularly, on [Formula: see text]. Also, within the framework of standard three active neutrinos, we find that effective Majorana mass [Formula: see text] can be vanishingly small if neutrino masses observe normal hierarchy. However, the same is not valid for inverted hierarchical neutrino masses. The predictions for Majorana phases [Formula: see text] and [Formula: see text] have also been obtained and shown as scatter plots. We also examine the condition [Formula: see text] within the framework wherein fermion sector has been extended by the addition of either one or two sterile neutrinos. The condition of vanishing effective Majorana mass is found to be inconsistent with the recent measurement of [Formula: see text] in these classes of models except for [Formula: see text], [Formula: see text] neutrino mass scheme for small values of the lightest neutrino mass, [Formula: see text].

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 Oscillating Neutrinos and Majorana Neutrino Masses

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 29
Author(s):  
Harald Fritzsch
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Neutrinoless Double Beta Decay ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Quark Masses ◽  
Mass Matrices ◽  
The Matrix ◽  
Flavor Mixing

We discuss the mass matrices with texture zeros for the quarks and leptons. The flavor mixing angles for the quarks are functions of the quark masses and can be calculated. The results agree with the experimental data. The texture zero mass matrices for the leptons and the see-saw mechanism are used to derive relations between the matrix elements of the lepton mixing matrix and the ratios of the neutrino masses. Using the measured neutrino mass differences, the neutrino masses can be calculated. The neutrinoless double beta decay is discussed. The effective Majorana neutrino mass, describing the neutrinoless double beta decay, can be calculated—it is about 4.6 meV. The present experimental limit is at least twenty times larger.

A SIGMA MODEL FOR NEUTRINO MASSES AND MIXINGS AND DECAY

1991 ◽  
Vol 06 (39) ◽  
pp. 3583-3590 ◽  
Author(s):  
SAUL BARSHAY
Keyword(s):  
Sigma Model ◽  
Neutrino Masses ◽  
Goldstone Bosons ◽  
The Masses ◽  
Neutrino Masses And Mixings

I consider the possibility that a sigma model is relevant for calculating the masses and mixings of Dirac neutrinos. New processes involving pairs of Goldstone bosons are predicted, in particular the decay [Formula: see text].

Neutrinoless double-beta decays: New insights

2017 ◽  
Vol 32 (14) ◽  
pp. 1730011 ◽  
Author(s):  
Z. Z. Xing ◽  
Z. H. Zhao
Keyword(s):  
Neutrino Mass ◽  
Mass Formula ◽  
Three Dimensional ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Two Dimensional ◽  
Mixing Angles ◽  
Flavor Mixing ◽  
Majorana Neutrino Mass ◽  
Beta Decays

We give some new insights into the effective Majorana neutrino mass [Formula: see text] responsible for the neutrinoless double-beta [Formula: see text] decays. We put forward a three-dimensional way of plotting [Formula: see text] against the lightest neutrino mass and the Majorana phases, which can provide more information as compared with the two-dimensional one. With the help of such graphs we discover a novel threshold of [Formula: see text] in terms of the neutrino masses and flavor mixing angles: [Formula: see text] in connection with [Formula: see text] and [Formula: see text], which can be used to signify observability of the future [Formula: see text]-decay experiments. Fortunately, the possibility of [Formula: see text] turns out to be very small, promising a hopeful prospect for the [Formula: see text]-decay searches.

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