NEUTRINO MASSES AND TeV SCALE RESONANT LEPTOGENESIS FROM SUPERSYMMETRY BREAKING

2006 ◽  
Vol 21 (21) ◽  
pp. 1629-1646 ◽  
Author(s):  
STEPHEN M. WEST

We review a class of supersymmetric models in which the light neutrino masses result from higher-dimensional supersymmetry-breaking terms in the MSSM super- and Kähler-potentials. The mechanism used in these models is closely related to the Giudice–Masiero mechanism for the MSSM μ parameter and leads to TeV-scale right-handed neutrino and sneutrino states. In these models, the dominant contribution to the light neutrino (Majorana) mass matrix is a one-loop term with a sub-dominant tree-level "seesaw" contribution. It is also shown that it is possible to construct a natural model of TeV-scale leptogenesis via the resonant behavior of the one-loop self-energy contribution to the right-handed neutrino (Ni) decay. This model addresses the primary problems of previous phenomenological studies of low-energy leptogenesis: a rational for TeV-scale right-handed neutrinos with small Yukawa couplings; the origin of the tiny, but non-zero mass splitting required between at least two Ni masses; and the necessary non-trivial breaking of flavor symmetries in the right-handed neutrino sector.

2019 ◽  
Vol 34 (19) ◽  
pp. 1950098 ◽  
Author(s):  
Teruyuki Kitabayashi

As the first topic, we propose a new parametrization of the complex Yukawa matrix in the scotogenic model. The new parametrization is compatible with the particle data group parametrization of the neutrino sector. Some analytical expressions for the neutrino masses with the new parametrization are shown. As the second topic, we consider the phenomenology of the scotogenic model with the one-zero-textures of the neutrino flavor mass matrix. One of the six patterns of the neutrino mass matrix is favorable for the real Yukawa matrix. On the other hand, for the complex Yukawa matrix, five of the six patterns are compatible with observations of the neutrino oscillations, dark matter relic abundance and branching ratio of the [Formula: see text] process.


2021 ◽  
Vol 36 (02) ◽  
pp. 2150010
Author(s):  
M. C. rodriguez

We build a supersymmetric model with [Formula: see text] gauge symmetry, with a global [Formula: see text] symmetry. The [Formula: see text] symmetry is necessary to keep the proton stable at least at tree level. There is also a global [Formula: see text] symmetry, where [Formula: see text] and [Formula: see text] are the usual baryonic and leptonic numbers, respectively. We introduce three nonidentical right-handed neutrinos plus new scalars fields. After symmetry breaking, the right-handed neutrinos together with one left-handed neutrino get Majorana masses via the seesaw mechanism. The other two left-handed neutrinos get their Majorana masses at 1-loop level. We will also explain the mixing angle in the neutrino sector in agreement with the experimental data and we get several interesting candidates to the observed dark matter.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Tobias Felkl ◽  
Juan Herrero-García ◽  
Michael A. Schmidt

Abstract We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The constraint disfavours large hierarchies among the Yukawa couplings. We study the implications for the phenomenology of lepton-flavour universality, measurements of the W-boson mass, flavour violation in the charged-lepton sector and decays of the singly-charged scalar singlet. We also discuss the parameter space that can address the Cabibbo Angle Anomaly.


2011 ◽  
Vol 26 (07) ◽  
pp. 501-514 ◽  
Author(s):  
S. DEV ◽  
SHIVANI GUPTA ◽  
RADHA RAMAN GAUTAM

We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with μτ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors on the right-handed Majorana mass matrix having μτ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with μτ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass Mee, the absolute mass scale and the Majorana-type CP violating phases.


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.


2019 ◽  
Vol 79 (10) ◽  
Author(s):  
N. Anh Ky ◽  
N. T. Hong Van ◽  
D. Nguyen Dinh ◽  
P. Quang Van

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.


1993 ◽  
Vol 08 (10) ◽  
pp. 895-902 ◽  
Author(s):  
SUBHASH RAJPOOT

An SU(2)L×U(1)L×U(1)R model of electroweak interactions is presented in which the conventional fermions of the standard model are left-handed doublets under SU(2)L× U(1)L and are right-handed singlets under U(1) R . The triangle anomalies are canceled by adding vector-like singlet fermions. Neutrinos are massless at the tree level due to a discrete symmetry and acquire tiny finite masses at the one-loop level due to the exchange of two charged scalar singlets. The singlet scalars carry two units of lepton number.


2007 ◽  
Vol 22 (13) ◽  
pp. 939-948 ◽  
Author(s):  
ADRIAN PALCU

In this paper we consider a plausible scenario with conserved lepton number L = Le-Lμ-Lτwithin the framework of the exact solution of a particular 3-3-1 gauge model. We discuss the consequences of conserving this global leptonic symmetry from the viewpoint of the neutrino mass matrix constructed via special Yukawa terms (involving tensor products among Higgs triplets). We prove that the actual experimental data can naturally be reproduced by our scenario since soft breaking terms with respect to this lepton symmetry are properly introduced. As a consequence, our solution predicts for the neutrino sector the correct mass splitting ratio [Formula: see text], the inverted mass hierarchy, the correct values for the observed mixing angles ( sin2θ23≃0.5 and sin2θ12= 0.31) and the absolute mass of the lightest neutrino (m0~ 0.001 eV) independent of the breaking scale of the model.


2014 ◽  
Vol 29 (22) ◽  
pp. 1450113 ◽  
Author(s):  
Rupak Dutta ◽  
Upender Ch ◽  
Anjan K. Giri ◽  
Narendra Sahu

We discuss the role of lightest neutrino mass (m0) in the neutrino mass matrix, defined in a flavor basis, through a bottom-up approach using the current neutrino oscillation data. We find that if m0 < 10-3 eV , then the deviation δMν in the neutrino mass matrix from a tree-level, say tribimaximal neutrino mass matrix, does not depend on m0. As a result δMν's are exactly predicted in terms of the experimentally determined quantities such as solar and atmospheric mass squared differences and the mixing angles. On the other hand for m0 ≳10-3 eV , δMν strongly depends on m0 and hence cannot be determined within the knowledge of oscillation parameters alone. In this limit, we provide an exponential parametrization for δMν for all values of m0 such that it can factorize the m0 dependency of δMν from rest of the oscillation parameters. This helps us in finding δMν as a function of the solar and atmospheric mass squared differences and the mixing angles for all values of m0. We use this information to build up a model of neutrino masses and mixings in a top-down scenario which can predict large θ13 perturbatively.


2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Hiroshi Okada ◽  
Morimitsu Tanimoto

AbstractWe study quark and lepton mass matrices in the $$A_4$$ A 4 modular symmetry towards the unification of the quark and lepton flavors. We adopt modular forms of weights 2 and 6 for quarks and charged leptons, while we use modular forms of weight 4 for the neutrino mass matrix which is generated by the Weinberg operator. We obtain the successful quark mass matrices, in which the down-type quark mass matrix is constructed by modular forms of weight 2, but the up-type quark mass matrix is constructed by modular forms of weight 6. The viable region of $$\tau $$ τ is close to $$\tau =i$$ τ = i . Lepton mass matrices also work well at nearby $$\tau =i$$ τ = i , which overlaps with the one of the quark sector, for the normal hierarchy of neutrino masses. In the common $$\tau $$ τ region for quarks and leptons, the predicted sum of neutrino masses is 87–120 meV taking account of its cosmological bound. Since both the Dirac CP phase $$\delta _{CP}^\ell $$ δ CP ℓ and $$\sin ^2\theta _{23}$$ sin 2 θ 23 are correlated with the sum of neutrino masses, improving its cosmological bound provides crucial tests for our scheme as well as the precise measurement of $$\sin ^2\theta _{23}$$ sin 2 θ 23 and $$\delta _{CP}^\ell $$ δ CP ℓ . The effective neutrino mass of the $$0\nu \beta \beta $$ 0 ν β β decay is $$\langle m_{ee}\rangle =15$$ ⟨ m ee ⟩ = 15 –31 meV. It is remarked that the modulus $$\tau $$ τ is fixed at nearby $$\tau =i$$ τ = i in the fundamental domain of SL(2, Z), which suggests the residual symmetry $$Z_2$$ Z 2 in the quark and lepton mass matrices. The inverted hierarchy of neutrino masses is excluded by the cosmological bound of the sum of neutrino masses.


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