Related papers: An allowed window for heavy neutral leptons below …
We consider the neutrino sector of a Standard Model with four generations. While the three light neutrinos can obtain their masses from a variety of mechanisms with or without new neutral fermions, fourth-generation neutrinos need at least…
The electron and muon number violating muonium-antimuonium oscillation process can proceed provided neutrinos have non-zero masses and mix among the various generations. Modifying the Standard Model only by the inclusion of singlet right…
In this report we discuss the main theories to understand the origin of baryon and lepton number violation in physics beyond the Standard Model. We present the theoretical predictions for rare processes such as neutrinoless double beta…
We propose a minimal and motivated extension of the Standard Model characterised by an approximate lepton number conservation, which is able to simultaneously generate neutrino masses and to account for a successful baryogenesis via…
The current experimental values of anomalous magnetic moments of muon and electron deviate from the Standard Model predictions by few standard deviations, which might be a hint of new physics. The sizes and signs of these deviations are…
Neutrino oscillations are a phenomenon that has been observed for over two decades and leads to the conclusion that neutrinos have mass. The Standard Model predicts massless neutrinos, and so neutrinos require physics beyond the Standard…
A nonuniversal abelian extension $\mathrm{U(1)}_{X}$ free from chiral anomalies is introduced into the Standard Model (SM), in order to evaluate its suitability in addressing the fermion mass hierarchy (FMH) by using seesaw mechanisms…
Supersymmetry is one of the most plausible extensions of the Standard Model, since it is well motivated by the hierarchy problem, supported by measurements of the gauge coupling strengths, consistent with the suggestion from precision…
We consider the generation of a baryon asymmetry in an extension of the Standard Model with two singlet Majorana fermions that are degenerate above the electroweak phase transition. The model can explain neutrino masses as well as the…
The observed baryon asymmetry of the Universe is suitably created in thermal leptogenesis through the out-of-equilibrium decay of $N_1$, the lightest of the three heavy singlet neutral fermions which anchor the seesaw mechanism to obtain…
Recently a minimalistic scenario has been developed to explain dark matter and tiny but nonzero neutrino masses. In this scenario, a new scalar called SLIM plays the role of the dark matter. Neutrinos achieve Majorana mass through a…
The observation of neutrino oscillations and hence non-zero neutrino masses provided a milestone in the search for physics beyond the Standard Model. But even though we now know that neutrinos are massive, the nature of neutrino masses,…
The possibility that the accurately known value of the Z width might furnish information about the coupling of two neutrinos to the Majoron (Nambu-Goldstone boson of spontaneous lepton number violation) is proposed and investigated in…
We derive strong contraints on the Yukawa couplings and the vacuum expectation value in the singlet majoron model, taking into account the possibility of a small gravitationally induced mass for the majoron. If the present baryon asymmetry…
We determine the neutrino mixing and mass parameters that are allowed by the Super-Kamiokande atmospheric neutrino data in a three-neutrino model with one mass-squared difference contributing to the oscillations. We find that although…
We argue that simpler fermionic contents, responsible for the extension of the standard model with gauged lepton and baryon charges, can be constructed by assuming existence of so-called leptoquarks (j,k) with exotic electric charges…
We propose a realistic model with Majorana neutrinos in the framework of unifying the three generations of fermions by point interactions in an extra dimension. This model can simultaneously explain the origin of fermion generations,…
We study experimental and cosmological constraints on the extension of the Standard Model by three right handed neutrinos with masses between those of the pion and W boson. We combine for the first time direct, indirect and cosmological…
We present a comprehensive overview of an extension of the Standard Model that contains three right-handed (sterile) neutrinos with masses below the electroweak scale [the Neutrino Minimal Standard Model, (nuMSM)]. We consider the history…
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…