scholarly journals Theoretical and Phenomenological Status of Neutrino Physics: A Brief Review

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Surender Verma
Keyword(s):  
Neutrino Mass ◽  
Particle Physics ◽  
Recent Observation ◽  
New Physics ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Mixing Parameters ◽  
Phenomenological Studies ◽  
The Status ◽  
Free Parameters

We present an overview of recent progress in the theoretical and phenomenological studies of neutrino masses, lepton avor mixing, and CP violation. Firstly, We discuss the status of neutrino mass with in the Standard Model (SM) of particle physics. Then the possible ways in which neutrino mass terms can be included in the SM are discussed. The inclusion of new physics beyond the SM inevitably brings new parameters which are not constrained by the present experimental data on neutrino masses and mixing angles and, thus, are free parameters of the theory. We, also, discuss various theoretically motivated phenomenological approaches which can be used to reduce the number of free parameters and, thus, provide an excellent tool to understand the underlying physics of neutrino masses and mixings. Current experimental constraints on the neutrino mass spectrum and the lepton avor mixing parameters, including the recent observation of nonzeroθ13, have been summarized. Finally, We discuss the renewed interest in the possible existence of one or more sterile neutrinos and their phenomenology.

scholarly journals DIRAC NEUTRINO MASSES AND MIXING PARAMETERS IN A LEFT–RIGHT MODEL WITH MIRROR FERMIONS

2007 ◽  
Vol 22 (16n17) ◽  
pp. 2935-2943 ◽  
Author(s):  
R. GAITÁN ◽  
A. HERNÁNDEZ-GALEANA ◽  
J. M. RIVERA-REBOLLEDO ◽  
P. FERNÁNDEZ DE CÓRDOBA ◽  
S. RODRIGUEZ-ROMO
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Expectation Value ◽  
Mixing Parameters ◽  
Order Of Magnitude ◽  
Free Parameters ◽  
The Masses

In this work we consider a left–right model containing mirror fermions with gauge group SU (3)C ⊗ SU (2)L ⊗ SU (2)R ⊗ U (1)Y′. The model has several free parameters which here we have calculated by using the recent values for the squared-neutrino mass differences. Lower bound for the mirror vacuum expectation value helped us to obtain crude estimations for some of these parameters. Also we estimate the order of magnitude of the masses of the standard and mirror neutrinos and numerical values for neutrino mixing angles.

scholarly journals Leptonic sum rules from flavour models with modular symmetries

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
J. Gehrlein ◽  
M. Spinrath
Keyword(s):  
Neutrino Mass ◽  
Sum Rules ◽  
Mass Scale ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Mixing Parameters ◽  
Neutrino Experiments ◽  
Parameter Ranges ◽  
Absolute Neutrino Mass ◽  
Analytical Expressions

Abstract Sum rules in the lepton sector provide an extremely valuable tool to classify flavour models in terms of relations between neutrino masses and mixing parameters testable in a plethora of experiments. In this manuscript we identify new leptonic sum rules arising in models with modular symmetries with residual symmetries. These models simultaneously present neutrino mass sum rules, involving masses and Majorana phases, and mixing sum rules, connecting the mixing angles and the Dirac CP-violating phase. The simultaneous appearance of both types of sum rules leads to some non-trivial interplay, for instance, the allowed absolute neutrino mass scale exhibits a dependence on the Dirac CP-violating phase. We derive analytical expressions for these novel sum rules and present their allowed parameter ranges as well as their predictions at upcoming neutrino experiments.

scholarly journals PERTURBED INVARIANT UNDER A CYCLIC PERMUTATION WITH TRACE OF NEUTRINO MASS MATRIX REMAIN CONSTANT

2011 ◽  
Vol 26 (08) ◽  
pp. 567-574 ◽  
Author(s):  
ASAN DAMANIK
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Cyclic Permutation ◽  
Neutrino Mass Matrix ◽  
Neutrino Masses ◽  
Inverted Hierarchy ◽  
Seesaw Mechanism ◽  
Mixing Parameters ◽  
Difference Formula ◽  
Mass Matrices

We construct a neutrino mass matrix Mν via a seesaw mechanism with perturbed invariant under a cyclic permutation by introducing a parameter δ into the diagonal elements of Mν with the assumption that trace of the perturbed Mν is equal to trace of the unperturbed Mν. We found that the perturbed neutrino mass matrices Mν can predict the mass-squared difference [Formula: see text] with the possible hierarchy of neutrino mass is normal or inverted hierarchy. By using the advantages of the mass-squared differences and mixing parameters data from neutrino oscillation experiments, we then have neutrino masses in inverted hierarchy with masses: |m1| = 0.101023 eV , |m2| = 0.101428 eV and |m3| = 0.084413 eV .

scholarly journals Effects of active–sterile neutrino mixing during primordial nucleosynthesis

2014 ◽  
Vol 23 (12) ◽  
pp. 1450080 ◽  
Author(s):  
Osvaldo Civitarese ◽  
Mercedes Elisa Mosquera ◽  
María Manuela Sáez
Keyword(s):  
Neutrino Mass ◽  
Sterile Neutrino ◽  
Distribution Functions ◽  
Light Nuclei ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
A Value ◽  
Active Neutrino ◽  
Observable Data ◽  
Free Parameters

In the present work, we discuss the effects of the inclusion of sterile–active neutrino oscillations during the production of primordial light-nuclei. We assume that the sterile neutrino mass-eigenstate might oscillate with the two lightest active neutrino mass-eigenstates, with mixing angles ϕ1 and ϕ2. We also allow a constant renormalization (represented by a parameter (ζ)) of the sterile neutrino occupation factor. Taking ζ and the mixing angles as free parameters, we have computed distribution functions of active and sterile neutrinos and primordial abundances. Using observable data we set constrains in the free parameters of the model. It is found that the data on primordial abundances are consistent with small mixing angles and with a value of ζ smaller than 0.65 at 3σ level.

scholarly journals Can the Majorana Neutrino CP-Violating Phases be Restricted?

2003 ◽  
Vol 18 (26) ◽  
pp. 1803-1808 ◽  
Author(s):  
Koichi Matsuda ◽  
Takeshi Fukuyama ◽  
Hiroyuki Nishiura
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Mixing Parameters ◽  
Double Beta Decay Experiment

We reanalyze the constraints in neutrino masses and MNS lepton mixing parameters using the new data from the terrestrial (KamLAND) and astrophysical (WMAP) observations together with the Heidelberg–Moscow double beta decay experiment. It leads us to the almost degenerate or inverse hierarchy neutrino mass scenario. We discuss the possibility of getting the bound for the Majorana CP-violating phase.

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.

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.

scholarly journals Neutrino masses in an $$SU(4)\otimes U(1)$$-electroweak model with a scalar decuplet

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
N. Anh Ky ◽  
N. T. Hong Van ◽  
D. Nguyen Dinh ◽  
P. Quang Van
Keyword(s):  
Symmetry Breaking ◽  
Neutrino Mass ◽  
Particle Physics ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Coupling Coefficients ◽  
Mass Model ◽  
Yukawa Couplings ◽  
Distribution Shape ◽  
Independent Distribution

Abstract A neutrino mass model is suggested within an $$SU(4)\otimes U(1)$$SU(4)⊗U(1)-electroweak theory. The smallness of neutrino masses can be guaranteed by a seesaw mechanism realized through Yukawa couplings to a scalar SU(4)-decuplet. In this scheme the light active neutrinos are accompanied by heavy neutrinos, which may have masses at different scales, including those within eV–MeV scales investigated quite intensively in both particle physics and astrophysics/cosmology. The flavour neutrinos are superpositions of light neutrinos and a small fraction of heavy neutrinos with the mixing to be determined by the model’s parameters (Yukawa coupling coefficients or symmetry breaking scales). The distribution shape of the Yukawa couplings can be visualized via a model-independent distribution of the neutrino mass matrix elements derived by using the current experimental data. The absolute values of these Yukawa couplings are able to be determined if the symmetry breaking scales are known, and vice versa. With reference to several current and near future experiments, detectable bounds of these heavy neutrinos at different mass scales are discussed and estimated.

BOUNDS ON MIXING ANGLES OF FERMIONS WITH THEIR EXOTIC PARTNERS USING LEP 1990 DATA

1991 ◽  
Vol 06 (32) ◽  
pp. 2921-2933 ◽  
Author(s):  
G. BHATTACHARYYA ◽  
A. DATTA ◽  
S. N. GANGULI ◽  
A. RAYCHAUDHURI
Keyword(s):  
Cross Sections ◽  
Axial Vector ◽  
New Physics ◽  
Upper Bounds ◽  
Tree Level ◽  
Mixing Angles ◽  
The Standard Model ◽  
Model Mixing ◽  
Free Parameters ◽  
Combined Data

We have studied the bounds on mixing angles of fermions with their exotic partners which may stem from different possibilities of new physics. The tree level effects of mixing have been taken care of by a modification of the effective vector and axial-vector couplings of Z to the fermions. The radiative corrections arising from new physics of exotic fermions are assumed to be negligible; as a result the ρ parameter and the effective sin 2 θw are calculated within the framework of the Standard Model. Mixing angles have been treated as free parameters during simultaneous fits to the combined data of cross-sections and lepton asymmetries from the four LEP experiments which have collected over 550,000 Z0 decays in 1990. Fitted values of mixing angles and the upper bounds at 90% C. L. are discussed.

CHARM DECAYS WITHIN THE STANDARD MODEL AND BEYOND

2006 ◽  
Vol 21 (08n09) ◽  
pp. 1697-1709 ◽  
Author(s):  
MARINA ARTUSO
Keyword(s):  
Standard Model ◽  
Charm Quark ◽  
New Physics ◽  
Charm Physics ◽  
Experimental Information ◽  
Charm Decays ◽  
Mixing Parameters ◽  
The Standard Model ◽  
The Status ◽  
Good Agreement

The charm quark has unique properties that make it a very important probe of many facets of the Standard Model. New experimental information on charm decays is becoming available from dedicated experiments at charm factories, and through charm physics programs at the b-factories and hadron machines. In parallel, theorists are working on matrix element calculations based on unquenched lattice QCD, that can be validated by experimental measurements and affect our ultimate knowledge of the quark mixing parameters. Recent predictions are compared with corresponding experimental data and good agreement is found. Charm decays can also provide unique new physics signatures; the status of present searches is reviewed. Finally, charm data relevant for improving beauty decay measurements are presented.

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