Generating Majorana neutrino masses with loops

2015 ◽  
Vol 30 (24) ◽  
pp. 1530018
Author(s):  
Chao-Qiang Geng

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.

2015 ◽  
Vol 30 (04n05) ◽  
pp. 1530001 ◽  
Author(s):  
S. M. Bilenky ◽  
C. Giunti

In the Standard Model the total lepton number is conserved. Thus, neutrinoless double-β decay, in which the total lepton number is violated by two units, is a probe of physics beyond the Standard Model. In this review we consider the basic mechanism of neutrinoless double-β decay induced by light Majorana neutrino masses. After a brief summary of the present status of our knowledge of neutrino masses and mixing and an introduction to the seesaw mechanism for the generation of light Majorana neutrino masses, in this review we discuss the theory and phenomenology of neutrinoless double-β decay. We present the basic elements of the theory of neutrinoless double-β decay, our view of the present status of the challenging problem of the calculation of the nuclear matrix element of the process and a summary of the experimental results.


2007 ◽  
Vol 16 (01) ◽  
pp. 1-50 ◽  
Author(s):  
WAN-LEI GUO ◽  
ZHI-ZHONG XING ◽  
SHUN ZHOU

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.


2003 ◽  
Vol 18 (26) ◽  
pp. 1803-1808 ◽  
Author(s):  
Koichi Matsuda ◽  
Takeshi Fukuyama ◽  
Hiroyuki Nishiura

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.


2020 ◽  
Vol 9 ◽  
pp. 14
Author(s):  
A. Faessler

The standard model predicts a ratio of 2 for the number of atmospheric muon to electron neutrinos, while super-Kamiokande and others measure a much smaller value (1.30±0.02 for super-Kamiokande). Super-Kamiokande is also able to measure roughly the direction and the energy of the neutrinos. The zenith-angle dependence for the muon neutrinos suggests that the muon neutrinos oscillate into a third neutrino species, either into the r neutrino or a sterile neutrino. This finding is inves- tigated within the supersymmetric model. The neutrinos mix with the neutralinos, this meaning the wino, the bino and the two higgsinos. The 7 x 7 mass matrix is calculated on the tree level. One finds that the mass matrix has three linearly dependent rows, which means that two masses are zero. They are identified with the two lightest neutrino masses. The fit of the super-Kamiokande data to oscillations between three neutrinos yields, together with the result of supersymmetry, that the third neutrino mass lies between 2x10^-2 and 10^-1 eV. The two lightest neutrino masses are in supersymmetry on the tree level zero. The averaged electron neutrino mass which is the essential parameter in the neutrinoless double-beta decay is given by {m_ve) ~ m_v3 P_ze < 0.8 x10^-2 eV (95% confidence limit). It is derived from the super-Kamiokande data in this supersymmetric model to be two orders smaller than the best value (1 eV) from the neutrinoless double-beta decay.


Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 29
Author(s):  
Harald Fritzsch

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.


2016 ◽  
Vol 25 (4) ◽  
pp. 291
Author(s):  
Vo Van Vien ◽  
Hoang Ngoc Long ◽  
Phan Ngoc Thu

We show that the neutrino mass matrix of the Zee-Babu model isable to fit the recent data on neutrino masses and mixingwith non-zero $\theta_{13}$ in the inverted neutrino mass hierarchy. The results show that the Majorana  phases are equal to zero and the Dirac phase ($\de$) ispredicted to either $0$ or $\pi$, i. e, there is no CP violation in the Zee-Babu model at the two loop level. The effective mass governingneutrinoless double beta decay and the sum of neutrino masses areconsistent with the recent analysis.


2009 ◽  
Vol 24 (31) ◽  
pp. 2491-2495 ◽  
Author(s):  
ERNEST MA

The inverse seesaw mechanism of neutrino mass, i.e. [Formula: see text], where ∊L is small, is discussed in the context of the U(1)Σ model. This is a gauge extension of the Standard Model of particle interactions with lepton triplets (Σ+, Σ0, Σ-) as (Type III) seesaw anchors for obtaining small Majorana neutrino masses.


2014 ◽  
Vol 29 (38) ◽  
pp. 1450196 ◽  
Author(s):  
Hai-Bin Zhang ◽  
Guo-Hui Luo ◽  
Tai-Fu Feng ◽  
Shu-Min Zhao ◽  
Tie-Jun Gao ◽  
...  

The μνSSM, one of supersymmetric extensions beyond the Standard Model, introduces three singlet right-handed neutrino superfields to solve the μ problem and can generate three tiny Majorana neutrino masses through the seesaw mechanism. In this paper, we investigate the rare decay process [Formula: see text] in the μνSSM, under a minimal flavor violating assumption for the soft breaking terms. Constrained by the SM-like Higgs with mass around 125 GeV, the numerical results show that the new physics can fit the experimental data for [Formula: see text] and further constrain the parameter space.


2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Juan Herrero-García ◽  
Michael A. Schmidt

AbstractWe propose a model-independent framework to classify and study neutrino mass models and their phenomenology. The idea is to introduce one particle beyond the Standard Model which couples to leptons and carries lepton number together with an operator which violates lepton number by two units and contains this particle. This allows to study processes which do not violate lepton number, while still working with an effective field theory. The contribution to neutrino masses translates to a robust upper bound on the mass of the new particle. We compare it to the stronger but less robust upper bound from Higgs naturalness and discuss several lower bounds. Our framework allows to classify neutrino mass models in just 20 categories, further reduced to 14 once nucleon decay limits are taken into account, and possibly to 9 if also Higgs naturalness considerations and direct searches are considered.


2018 ◽  
Vol 47 ◽  
pp. 1860100
Author(s):  
Ng. K. Francis ◽  
Ankur Nath

Majorana CP violating phases coming from heavy right-handed Majorana mass matrices([Formula: see text]) are considered to estimate the masses of neutrinos. The effects of phases on quasi-degenerate neutrinos mass matrix obeying [Formula: see text] symmetry predicts the results consistent with observations for (i) solar mixing angle([Formula: see text]) below TBM, (ii) absolute neutrino mass parameters[[Formula: see text]] in neutrinoless double beta([Formula: see text]) decay, and (iii) cosmological upper bound [Formula: see text]. Analysis is carried out through parameterization of light left-handed Majorana neutrino matrices ([Formula: see text]) using only two unknown parameters ([Formula: see text]) within [Formula: see text] symmetry. We consider the charge lepton and up quark matrices as diagonal form of Dirac neutrino mass matrix ([Formula: see text]), and [Formula: see text] are generated using [Formula: see text] through inversion of Type-I seesaw formula. The analysis shows that the masses of neutrinos are in agreement with the upper bound from cosmology and neutrinoless double beta decay. The results presented in this article will have important implications in discriminating the neutrinos mass models.


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