Related papers: Radiatively induced electron and electron-neutrino…
In this talk we show how a natural neutrino mass hierarchy can follow from the type I see-saw mechanism, and a natural neutrino mass degeneracy from the type II see-saw mechanism, where the bi-large mixing angles can arise from either the…
The Standard Model includes neutrinos as massless particles, but neutrino oscillations showed that neutrinos are not massless. A simple extension of adding gauge singlet fermions to the particle spectrum allows normal Yukawa mass terms for…
Neutrinoless double beta decay, which is a very old and yet elusive process, is reviewed. Its observation will signal that lepton number is not conserved and the neutrinos are Majorana particles. More importantly it is our best hope for…
In the conventional seesaw models of neutrino masses, leptogenesis occurs at a very high scale. Three approaches have been discussed in the literature to lower the scale of leptogenesis: mass degeneracy, hierarchy of couplings and…
We derive the lower bound on absolute scale of lightest neutrino mass for normal hierarchy and inverted hierarchy pattern of light neutrinos by studying the new physics contributions to charged lepton flavour violating decays and…
We present an approach of mass generation for Standard Model particles in which fermions acquire masses from their interactions with physical vacuum and gauge bosons acquire masses from charge fluctuations of vacuum. A remarkable fact of…
A new model of radiative neutrino masses generated via two-loop diagrams is proposed involving a charge 2/3 vector-like quark and a doublet of leptoquark scalars. This model predicts one of the neutrinos to be massless and admits both the…
The linear seesaw mechanism provides a simple way to generate neutrino masses. In addition to Standard Model particles, it includes quasi-Dirac leptons as neutrino mass mediators, and a leptophilic scalar doublet seeding small neutrino…
We present a model which supplements the Standard Electroweak Model with three right-handed neutrinos and one extra scalar doublet which does not develop a vacuum expectation value. With the aid of a discrete symmetry the neutrinos are kept…
Tiny neutrino masses can arise naturally via loop diagrams. After a brief review of the radiative mass generation mechanism, I present a new model wherein TeV scale leptoquark scalars induce neutrino masses via two--loop diagrams. This…
We propose a phenomenological form of the charged lepton mass matrix, which extends the idea of ``lopsided'' mass matrix in the literature. The features of the form are that both the 2-3 and 1-3 elements of the charged lepton mass matrix…
The complexity of radiative neutrino-mass models can be judged by: (i) whether they require the imposition of ad hoc symmetries, (ii) the number of new multiplets they introduce, and (iii) the number of arbitrary parameters that appear.…
In the 331 model, lepton number may be explicitly broken by trilinear scalar self couplings. This leads to neutrino masses proportional to the cube of the corresponding charged lepton mass, with consequences for solar neutrinos and for hot…
A new mechanism is proposed for generating neutrino masses radiatively through a non-minimal coupling to gravity of fermionic bilinears involving massive neutral fermions. Such coupling terms can arise in theories where the gravity sector…
A candidate for the simple empirical neutrino mass formula is found, predicting the mass proportion m_1:m_2:m_3 = 0:4:24 and so, the mass ratio Delta m^2_{32}/Delta m^2_{21} = 35 not inconsistent with its experimental estimate. It involves…
We construct new invariants and give several theorems which determine in general (i) the number of physically meaningful phases in charged lepton and neutrino mass matrices and (ii) which elements of these matrices can be rendered real by…
Generation of the neutrino masses and leptogenesis (LG) in the Standard Model extended by the heavy Majorana fermions is considered. Classification of LG scenarios according to the new fermion mass spectra is given, where singlet-triplet LG…
Relativistic electrons colliding with intense counterpropagating laser pulses are expected to lose energy through radiation reaction. However, we reveal a counterintuitive regime where reflected leptons (including incident electrons,…
In the supersymmetric extensions of the standard model, neutrino masses and leptogenesis requires existence of new particles. We point out that if these particles with lepton number violating interactions have standard model gauge…
We build the first 3-3-1 model based on the $\Delta (27)$ discrete group symmetry, consistent with fermion masses and mixings. In the model under consideration, the neutrino masses are generated from a combination of type-I and type-II…