scholarly journals Neutrino Mass Spectrum: Present Indication and Future Prospect

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 56
Author(s):  
Son Cao ◽  
Nguyen T. Hong Van ◽  
Tran V. Ngoc ◽  
Phan T. Quyen
Keyword(s):  
Mass Spectrum ◽  
Neutrino Mass ◽  
Future Prospect ◽  
Precise Determination ◽  
Beyond The Standard Model ◽  
Know How ◽  
The Standard Model ◽  
Neutrino Mass Spectrum ◽  
Using Data

The fact that neutrinos are massive has been the most crucial evidence of physics beyond the Standard Model of elementary particles. To date, we still do not know how neutrinos get mass and why their mass is much smaller than that of their charged fermion cousins. The precise determination of the neutrino mass spectrum has become one of the central tasks of neutrino physics, providing critical input for understanding the nature of neutrino mass and extending our model. The present landscape of the neutrino mass spectrum is reviewed and explored in this article using data from the neutrino oscillation, cosmology, and beta decay. In addition, we discuss the possibility of relevant programs elucidating the neutrino mass spectrum in the coming decades.

scholarly journals Conditions for statistical determination of the neutrino mass spectrum in radiative emission of neutrino pairs in atoms

2016 ◽  
Vol 93 (1) ◽  
Author(s):  
Ningqiang Song ◽  
R. Boyero Garcia ◽  
J. J. Gomez-Cadenas ◽  
M. C. Gonzalez-Garcia ◽  
A. Peralta Conde ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Neutrino Mass ◽  
Radiative Emission ◽  
Neutrino Mass Spectrum ◽  
Statistical Determination

Generating Majorana neutrino masses with loops

2015 ◽  
Vol 30 (24) ◽  
pp. 1530018
Author(s):  
Chao-Qiang Geng
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Neutrino Mass Spectrum ◽  
Doubly Charged ◽  
Global Fitting

We give a review on neutrino models in which Majorana neutrino masses are generated radiatively through loop diagrams. In particular, we concentrate on the two-loop models which contain extra doubly charged singlet [Formula: see text] and triplet [Formula: see text] scalars beyond the Standard Model so that the new Yukawa [Formula: see text] and effective [Formula: see text] couplings can be induced. In these two-loop models, we find that the neutrino mass spectrum is a normal hierarchy and the rate of the neutrinoless double beta decay [Formula: see text] can be large as it is dominated by the short-distance tree contribution. In addition, by using the neutrino oscillation data and comparing with the global fitting result in the literature, we find a unique neutrino mass matrix and predict the Dirac and two Majorana CP phases to be [Formula: see text], [Formula: see text] and [Formula: see text] with [Formula: see text], respectively.

scholarly journals Tests of Lepton Flavour Universality at LHCb

2018 ◽  
Vol 46 ◽  
pp. 1860070
Author(s):  
Anna Lupato
Keyword(s):  
Standard Model ◽  
Beyond The Standard Model ◽  
Centre Of Mass ◽  
Gauge Bosons ◽  
B Quarks ◽  
Clear Sign ◽  
The Standard Model ◽  
8 Tev ◽  
Using Data ◽  
Lepton Flavour

In the Standard Model the electroweak coupling of the gauge bosons to leptons is independent of the lepton flavour. Semileptonic and rare decays of b quarks provide an ideal laboratory to test this property. Any violation of Lepton Flavour Universality would be a clear sign of physics beyond the Standard Model. In this work a review of the Lepton Flavour Universality tests performed using data collected by the LHCb experiment in 2011 and 2012 at a centre of mass energy of 7 and 8 TeV is presented.

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.

τ LEPTON PHYSICS

1998 ◽  
Vol 13 (05) ◽  
pp. 695-739 ◽  
Author(s):  
GHITA RAHAL-CALLOT
Keyword(s):  
Neutral Current ◽  
Branching Fractions ◽  
New Physics ◽  
Precise Determination ◽  
Energy Scale ◽  
Hadronic Decay ◽  
Charged Current ◽  
Beyond The Standard Model ◽  
Decay Channels

General properties of the τ leptons are reviewed using the recent measurements of production and decay of τ leptons. The improvements in the knowledge of the τ mass and the limits on ντ mass are reported. New improved measurements of the τ polarization and asymmetries performed at LEP and SLC prove a measurement of the axial and vector part of the neutral current at the per mil level. For the leptonic charged current, no deviation from the V–A Lorentz structure of the current is observed. Improvements on the lifetime and leptonic branching fractions allow a check of the charged current universality at the 0.5% level. New hadronic decay channels have been measured, mainly those involving kaons and η mesons. A precise determination of αs at the τ mass energy scale is performed. Finally, tests of possible new physics beyond the Standard Model are discussed.

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