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 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 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.

NEUTRINO MIXING, LEPTONIC CP VIOLATION, THE SEESAW MECHANISM AND BEYOND

2010 ◽  
Vol 25 (23) ◽  
pp. 4325-4337 ◽  
Author(s):  
S. T. PETCOV
Keyword(s):  
Cp Violation ◽  
Neutrino Mass ◽  
Baryon Asymmetry ◽  
Neutrino Mixing ◽  
Mass Generation ◽  
Seesaw Mechanism ◽  
Mixing Matrix ◽  
Neutrino Mass Generation ◽  
The Universe

The phenomenology of 3-neutrino mixing and of the related Dirac and Majorana leptonic CP violation is reviewed. The leptogenesis scenario of generation of the baryon asymmetry of the Universe, which is based on the see-saw mechanism of neutrino mass generation, is considered. The results showing that the CP violation necessary for the generation of the baryon asymmetry of the Universe in leptogenesis can be due exclusively to the Dirac and/or Majorana CP-violating phase(s) in the neutrino mixing matrix U are briefly reviewed.

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 Leptonic CP violation and leptogenesis

2014 ◽  
Vol 29 (11n12) ◽  
pp. 1430028 ◽  
Author(s):  
S. T. Petcov
Keyword(s):  
Cp Violation ◽  
Neutrino Mass ◽  
Mass Scale ◽  
Baryon Asymmetry ◽  
Current Status ◽  
Neutrino Mixing ◽  
Mass Generation ◽  
Mixing Matrix ◽  
Neutrino Mass Generation ◽  
The Universe

The phenomenology of 3-neutrino mixing, the current status of our knowledge about the 3-neutrino mixing parameters, including the absolute neutrino mass scale, and of the Dirac and Majorana CP violation in the lepton sector, are reviewed. The problems of CP violation in neutrino oscillations and of determining the nature — Dirac or Majorana — of massive neutrinos, are discussed. The seesaw mechanism of neutrino mass generation and the related leptogenesis scenario of generation of the baryon asymmetry of the universe, are considered. The results showing that the CP violation necessary for the generation of the baryon asymmetry of the universe in leptogenesis can be due exclusively to the Dirac and/or Majorana CP-violating phase(s) in the neutrino mixing matrix U, are briefly reviewed.

scholarly journals Type-I thermal leptogenesis in $$Z_3$$-symmetric three Higgs doublet model

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Indrani Chakraborty ◽  
Himadri Roy
Keyword(s):  
Higgs Doublet ◽  
Baryon Asymmetry ◽  
Current Data ◽  
Type I ◽  
Mass Generation ◽  
Lepton Asymmetry ◽  
Strong Bound ◽  
Doublet Model ◽  
Neutrino Mass Generation ◽  
Scalar Sector

AbstractOur present work explores the possibility of neutrino mass generation through Type-I see-saw mechanism and provides an explanation of the baryon asymmetry of the Universe via thermal leptogenesis in the framework of a $$Z_3$$ Z 3 -symmetric three Higgs doublet model (3HDM) augmented with three right-handed neutrinos. Here the thermal leptogenesis is initiated by the out-of-equilibrium decay of the lightest heavy neutrino $$N_1$$ N 1 . The constraints arising out of the scalar sector put strong bound on the model parameter $$\tan \beta $$ tan β , which in turn takes part in the computation of the lepton asymmetry $$\epsilon $$ ϵ . Lepton asymmetry being converted partially into the baryon asymmetry by electroweak sphelaron processes, will account for the required baryon asymmetry satisfying the current data. We therefore analyse the parameter space consistent with the constraints arising from neutrino oscillation, lepton asymmetry and baryon asymmetry together, last one turning out to be the most stringent one.

scholarly journals Searching for radiative neutrino mass generation at the LHC

2015 ◽  
Vol 30 (12) ◽  
pp. 1530030 ◽  
Author(s):  
Raymond R. Volkas
Keyword(s):  
Neutrino Mass ◽  
Explicit Model ◽  
Mass Generation ◽  
International Conference ◽  
Massive Neutrinos ◽  
Neutrino Mass Generation ◽  
Neutrino Mass Models ◽  
Lhc I

In this talk (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015), I describe the general characteristics of radiative neutrino mass models that can be probed at the LHC. I then cover the specific constraints on a new, explicit model of this type.

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.

scholarly journals Testing radiative neutrino mass generation at the LHC

2007 ◽  
Vol 2007 (08) ◽  
pp. 022-022 ◽  
Author(s):  
Chian-Shu Chen ◽  
Chao-Qiang Geng ◽  
John N Ng ◽  
Jackson M.S Wu
Keyword(s):  
Neutrino Mass ◽  
Mass Generation ◽  
Neutrino Mass Generation
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