Related papers: Double type-II Dirac seesaw accompanied by Dirac f…
Single and double universal seesaw mechanisms and the hypothesis of universal strength for Yukawa couplings are applied to formulate a unified theory of fermion mass spectrum in a model based on an extended Pati-Salam symmetry. Five kinds…
Motivated by the fact that the origin of tiny Dirac neutrino masses via the standard model Higgs field and non-thermal dark matter populating the Universe via freeze-in mechanism require tiny dimensionless couplings of similar order of…
In this talk, we discuss a TeV scale model which would explain neutrino oscillation, dark matter, and baryon asymmetry of the Universe simultaneously by the dynamics of the extended Higgs sector and TeV-scale right-handed neutrinos. By the…
We consider the minimal seesaw model in which two gauge singlet right handed neutrinos with opposite lepton numbers are added to the Standard Model. In this model, the smallness of the neutrino mass is explained by the tiny lepton number…
With just the Standard Model Higgs doublet, there are only three types of seesaw models that generate light Majorana neutrino masses at tree level after electroweak spontaneous symmetry breaking. However, if there exist additional TeV…
With the motivation of simultaneously explaining dark matter and neutrino masses, mixing angles, we have invoked the Type-II seesaw model extended by an extra $SU(2)$ doublet $\Phi$. Moreover, we have imposed a $\mathbb{Z}_2$ parity on…
Heavy right-handed neutrinos are highly motivated due to their connection with the origin of neutrino masses via the seesaw mechanism. If the right-handed neutrino Majorana mass is at or below the weak scale, direct experimental discovery…
Using a mechanism which allows naturally small Dirac neutrino masses and its linkage to a dark gauge $U(1)_D$ symmetry, a realistic Dirac neutrino mass matrix is derived from $S_3$. The dark sector naturally contains a fermion singlet…
We explore the unification of gauge couplings and fermion masses in two different types of supersymmetric left-right models, one with Higgs triplets and the other with both Higgs triplets as well as bitriplets. The minimal versions of these…
We propose and study a novel extension of the Standard Model based on the B-L gauge symmetry that can account for dark matter and neutrino masses. In this model, right-handed neutrinos are absent and the gauge anomalies are canceled instead…
I introduce and sketch the main features of those see-saw models where a large atmospheric mixing can be achieved starting from nearly diagonal matrices for charged leptons, Dirac neutrinos and Majorana right-handed neutrinos. It turns out…
We consider the possibility to explain the recent $R_K$ and $R_{K ^*}$ anomalies in a 2-Higgs Doublet Model, known as Aligned, combined with a low scale seesaw mechanism generating light neutrino masses and mixings. In this class of models,…
We consider the possibility that Dirac neutrino masses may be a manifestation of chiral symmetry breaking via non-perturbative QCD dynamics. The key role played by light quarks in this mechanism can naturally lead to signals that are…
We propose a simple extension of the standard model by adding a fourth generation vector-like lepton doublet and show that if the fourth neutrino is a massive pseudo-Dirac fermion with mass in the few hundred GeV range and mass splitting of…
We study the possibility of generating tiny Dirac masses of neutrinos in Left-Right Symmetric Model (LRSM) without requiring the existence of any additional symmetries. The charged fermions acquire masses through a universal seesaw…
By extending the Standard Model with singlet-doublet fermions and triplet scalars, all odd under a new $Z_2$ symmetry, we introduce a radiative seesaw model that can simultaneously account for dark matter, explain the existence of neutrino…
Here we propose a realistic $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ electroweak gauge model with enlarged Higgs sector. The scheme allows for the natural implementation of a type II seesaw mechanism for Dirac neutrinos, while…
The asymmetric Higgs sector of one $SU(2)_L \times SU(2)_R$ bidoublet $(\phi_1^0,\phi_1^-;\phi_2^+,\phi_2^0)$ and one $SU(2)_R$ doublet [but no $SU(2)_L$ doublet] is considered in a nonsupersymmetric left-right extension of the standard…
We propose a supersymmetric scenario in which the small Yukawa couplings for the Dirac neutrino mass term are generated by the spontaneous-breaking of Pecci-Quinn symmetry. In this scenario, a right amount of dark matter relic density can…
We extend the singlet Majoron model of dark radiation by adding another singlet scalar of unit lepton charge. The spontaneous breaking of global $U(1)_L$ connects dark radiation with neutrino mass generation via the type-I seesaw mechanism.…