Related papers: GeV-scale neutrinos: interactions with mesons and …
We consider the Standard Model extended by right-handed neutrinos to explain massive neutrinos through the seesaw mechanism. The new fermion can be observed when it has a sufficiently small mass and large mixings to left-handed neutrinos.…
The existence of extra chiral generations is strongly disfavored by the precision electroweak data if all the extra fermions are heavier than m_Z. However fits as good as the SM can be obtained if one allows the new neutral leptons to have…
We derive general constraints on the mixing of heavy Seesaw neutrinos with the SM fields from a global fit to present flavour and electroweak precision data. We explore and compare both a completely general scenario, where the heavy…
An extension of the Standard Model by three singlet fermions with masses smaller than the electroweak scale allows to explain simultaneously neutrino oscillations, dark matter and baryon asymmetry of the Universe. We discuss the properties…
In the framework of the low-energy effective theory containing in addition to the Standard Model fields heavy neutral leptons (HNLs), we compute the decay rates of neutral and charged kaons into HNLs. We consider both…
Efforts to unify group-theoretically the standard-model gauge interactions with the generation structure of fermions and their mirror partners should be accompanied with the unification of the corresponding gauge couplings. In this paper…
If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino…
We give a pedagogical introduction to right-handed neutrinos as a simple extension to the Standard Model (SM), focussing on seesaw models and their possible experimental signatures. We preface this with a review of the lepton sector of the…
We search for an excess of electrons and positrons in the interplanetary space from the decays of heavy neutrinos produced in nuclear reactions in the Sun. Using measurements of the electron spectra in the MeV range from the Ulysses and…
We construct an explicit model implementing electromagnetic leptogenesis. In a simple extension of the Standard Model, a discrete symmetry forbids the usual decays of the right-handed neutrinos, while allowing for an effective coupling…
We discuss the phenomenology of a minimal model for GeV-scale Majorana dark matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. The theoretical framework extends the Standard Model by two $SU(2)_L$…
In this talk, I present a new framework to understand the long-standing fermion mass hierarchy puzzle. We extend the Standard Model gauge symmetry by an extra local U(1)_S symmetry, broken spontaneously at the electroweak scale. All the SM…
In the near future, fundamental interactions at high-energy scales may be most efficiently studied via precision measurements at low energies. A universal language to assemble and interpret precision measurements is the so-called SMEFT,…
We suggest a minimal model for GeV-scale Majorana Dark Matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. We show that there is an anti-correlation between the spin-independent DM-Nucleus scattering…
We consider a class of models in which the neutrinos acquire Majorana masses through mixing with singlet neutrinos that emerge as composite states of a strongly coupled hidden sector. In this framework, the light neutrinos are partially…
The vacuum stability condition of the Standard Model Higgs potential with mass in the range of 124-127 GeV puts an upper bound on the Dirac mass of the neutrinos. We study this constraint with the right-handed neutrino masses upto TeV…
An extension of the Standard Model is presented that leads to the possible existence of new gauge bosons with masses in the range of a few TeV. Due to the fact that their couplings to Standard Model fermions are strongly suppressed, it is…
We propose novel tree level seesaw mechanism with TeV-scale vectorlike Dirac mediators that produce Majorana masses of the known neutrinos. The gauge quantum number assignment to the Dirac mediators allows them to belong to a weak triplet…
The search strategy or the finding of new effects for heavy neutrinos often relies on their different decay channels to detectable particles. In particular in this work we study the decay of a Majorana neutrino with interactions obtained…
In this paper, we study the phenomenology of right-handed neutrino isosinglets. We consider the general situation where the neutrino masses are not necessarily given by $m_D^2/M$, where $m_D$ and $M$ are the Dirac and Majorana mass terms…