scholarly journals Singlet Fermion Assisted Dominant Seesaw with Lepton Flavor and Number Violations and Leptogenesis

2017 ◽  
Vol 2017 ◽  
pp. 1-24 ◽  
Author(s):  
M. K. Parida ◽  
Bidyut Prava Nayak
Keyword(s):  
Neutrino Mass ◽  
Experimental Tests ◽  
Fine Tuning ◽  
Type I ◽  
Type Ii ◽  
Mass Generation ◽  
Lepton Flavor ◽  
Mass Matrices ◽  
Neutrino Mass Generation ◽  
High Degree

Embedding type I seesaw in GUTs, left-right gauge theories, or even in extensions of the SM requires large right-handed neutrino masses making the neutrino mass generation mechanism inaccessible for direct experimental tests. This has been circumvented by introducing additional textures or high degree of fine-tuning in the Dirac neutrino or right-handed neutrino mass matrices. In this work we review another new mechanism that renders type I seesaw vanishing but other seesaw mechanisms dominant. Such mechanisms include extended seesaw, type II, linear, or double seesaw. The linear seesaw, double seesaw, and extended seesaw are directly verifiable at TeV scale. New observable predictions for lepton flavor and lepton number violations by ongoing searches are noted. Type II embedding in SO(10) also predicts these phenomena in addition to new mechanism for leptogenesis and displaced vertices mediated by gauge singlet fermions.

scholarly journals High Scale Type-II Seesaw, Dominant Double Beta Decay within Cosmological Bound and LFV Decays in SU(‎5)

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
M. K. Parida ◽  
Rajesh Satpathy
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Double Beta Decay ◽  
Type I ◽  
Mass Hierarchy ◽  
Type Ii ◽  
Inverted Hierarchy ◽  
Mass Generation ◽  
Neutrino Mass Generation ◽  
Physical Phenomena

Very recently novel implementation of type-II seesaw mechanism for neutrino mass has been proposed in SU(5) grand unified theory with a number of desirable new physical phenomena beyond the standard model. Introducing heavy right-handed neutrinos and extra fermion singlets, in this work we show how the type-I seesaw cancellation mechanism works in this SU(5) framework. Besides predicting verifiable LFV decays, we further show that the model predicts dominant double beta decay with normal hierarchy or inverted hierarchy of active light neutrino masses in concordance with cosmological bound. In addition a novel right-handed neutrino mass generation mechanism, independent of type-II seesaw predicted mass hierarchy, is suggested in this work.

scholarly journals Investigating two heavy neutral leptons neutrino seesaw mechanism at SHiP

2019 ◽  
Vol 34 (08) ◽  
pp. 1950047
Author(s):  
Marco Chianese ◽  
Damiano F. G. Fiorillo ◽  
Gennaro Miele ◽  
Stefano Morisi
Keyword(s):  
Neutrino Mass ◽  
Double Beta Decay ◽  
Type I ◽  
Mass Generation ◽  
Seesaw Mechanism ◽  
Mixing Angle ◽  
Mechanism Model ◽  
Neutrino Mass Generation ◽  
Generation Mechanisms ◽  
The Masses

One of the main purposes of SHiP experiment is to shed light on neutrino mass generation mechanisms like the so-called seesaw. We consider a minimal type-I seesaw neutrino mass mechanism model with two heavy neutral leptons (right-handed or sterile neutrinos) with arbitrary masses. Extremely high active-sterile mixing angle requires a correlation between the phases of the Dirac neutrino couplings. Actual experimental limits on the half-life of neutrinoless double beta decay [Formula: see text]-rate on the active-sterile mixing angle are not significative in constraining the masses or the mixing measurable by SHiP.

scholarly journals The Low-Scale Approach to Neutrino Masses

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Sofiane M. Boucenna ◽  
Stefano Morisi ◽  
José W. F. Valle
Keyword(s):  
Neutrino Mass ◽  
Cold Dark Matter ◽  
Short Review ◽  
Neutrino Masses ◽  
Lepton Flavor Violation ◽  
Mass Generation ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Phenomenological Potential ◽  
Neutrino Mass Generation

In this short review we revisit the broad landscape of low-scaleSU(3)c⊗SU(2)L⊗U(1)Ymodels of neutrino mass generation, with view on their phenomenological potential. This includes signatures associated to direct neutrino mass messenger production at the LHC, as well as messenger-induced lepton flavor violation processes. We also briefly comment on the presence of WIMP cold dark matter candidates.

scholarly journals The Nature of Massive Neutrinos

2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
S. T. Petcov
Keyword(s):  
Neutrino Mass ◽  
Current Data ◽  
Future Research ◽  
Type I ◽  
Neutrino Mixing ◽  
Mass Generation ◽  
Triplet Model ◽  
Majorana Neutrinos ◽  
Massive Neutrinos ◽  
Neutrino Mass Generation

The compelling experimental evidences for oscillations of solar, reactor, atmospheric, and accelerator neutrinos imply the existence of 3-neutrino mixing in the weak charged lepton current. The current data on the 3-neutrino mixing parameters are summarised and the phenomenology of 3-νmixing is reviewed. The properties of massive Majorana neutrinos and of their various possible couplings are discussed in detail. Two models of neutrino mass generation with massive Majorana neutrinos—the type I see-saw and the Higgs triplet model—are briefly reviewed. The problem of determining the nature, Dirac or Majorana, of massive neutrinos is considered. The predictions for the effective Majorana mass|〈m〉|in neutrinoless double-beta-((ββ)0ν-) decay in the case of 3-neutrino mixing and massive Majorana neutrinos are summarised. The physics potential of the experiments, searching for(ββ)0ν-decay for providing information on the type of the neutrino mass spectrum, on the absolute scale of neutrino masses, and on the Majorana CP-violation phases in the PMNS neutrino mixing matrix, is also briefly discussed. The opened questions and the main goals of future research in the field of neutrino physics are outlined.

scholarly journals Testing neutrino mass generation mechanisms from the lepton flavor violating decay of the Higgs boson

2016 ◽  
Vol 763 ◽  
pp. 352-357 ◽  
Author(s):  
Mayumi Aoki ◽  
Shinya Kanemura ◽  
Kodai Sakurai ◽  
Hiroaki Sugiyama
Keyword(s):  
Higgs Boson ◽  
Neutrino Mass ◽  
Mass Generation ◽  
Lepton Flavor ◽  
Neutrino Mass Generation ◽  
Generation Mechanisms

scholarly journals One colorful resolution to the neutrino mass generation, three lepton flavor universality anomalies, and the Cabibbo angle anomaly

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
We-Fu Chang
Keyword(s):  
Neutrino Mass ◽  
Parameter Space ◽  
Degrees Of Freedom ◽  
Dipole Moments ◽  
Baryon Number ◽  
Cabibbo Angle ◽  
Mass Generation ◽  
Lepton Flavor ◽  
Neutrino Mass Generation ◽  
The One

Abstract We propose a simple model to simultaneously explain four observed flavor anomalies while generating the neutrino mass at the one-loop level. Specifically, we address the measured anomalous magnetic dipole moments of the muon, ∆aμ, and electron, ∆ae, the observed anomaly of b → sl+l− in the B-meson decays, and the Cabibbo-angle anomaly. The model consists of four colorful new degrees of freedom: three scalar leptoquarks with the Standard Model quantum numbers (3, 3, −1/3), (3, 2, 1/6), and (3, 1, 2/3), and one pair of down-quark-like vector fermion in (3, 1, −1/3). The baryon number is assumed to be conserved for simplicity.Phenomenologically viable solutions with the minimal number of real parameters can be found to accommodate all the above-mentioned anomalies and produce the approximate, close to 1σ, neutrino oscillation pattern at the same time. From general consideration, the model robustly predicts: (1) neutrino mass is of the normal hierarchy type, and (2) $$ {\mathcal{M}}_{ee}^{\nu } $$ M ee ν ≲ 3 × 10−4 MeV.The possible UV origin to explain the flavor pattern of the found viable parameter space is briefly discussed. The parameter space can be well reproduced within a simple split fermion toy model.

scholarly journals A radiatively induced neutrino mass model with hidden local U(1) and LFV processes ℓi → ℓjγ, μ → eZ′ and μe → ee

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Takaaki Nomura ◽  
Hiroshi Okada ◽  
Yuichi Uesaka
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Mass Model ◽  
Mass Generation ◽  
Hidden Sector ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Neutrino Mass Generation

Abstract We investigate a model based on hidden U(1)X gauge symmetry in which neutrino mass is induced at one-loop level by effects of interactions among particles in hidden sector and the Standard Model leptons. Neutrino mass generation is also associated with U(1)X breaking scale which is taken to be low to suppress neutrino mass. Then we formulate neutrino mass matrix, lepton flavor violating processes and muon g − 2 which are induced via interactions among Standard Model leptons and particles in U(1)X hidden sector that can be sizable in our scenario. Carrying our numerical analysis, we show expected ratios for these processes when generated neutrino mass matrix can fit the neutrino data.

scholarly journals Relaxing cosmological neutrino mass bounds with unstable neutrinos

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Miguel Escudero ◽  
Jacobo Lopez-Pavon ◽  
Nuria Rius ◽  
Stefan Sandner
Keyword(s):  
Neutrino Mass ◽  
Particle Physics ◽  
Goldstone Boson ◽  
Mass Scale ◽  
Simple Extension ◽  
Type I ◽  
Mass Generation ◽  
Age Of The Universe ◽  
Neutrino Mass Models ◽  
The Right

Abstract At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model (ΛCDM), the Planck collaboration reports ∑mv< 0.12 eV at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe τν ≲ tU, represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state ν4 and a Goldstone boson ϕ, in which νi→ ν4ϕ decays can loosen the neutrino mass bounds up to ∑mv ∼ 1 eV, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a U(1)μ−τ flavor symmetry, which are otherwise in tension with the current bound on ∑mv.

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