Related papers: Modelling Heavy Neutral Leptons in Accelerator Bea…
There are three observables related to neutrino mass, namely the kinematic mass in direct searches, the effective mass in neutrino-less double beta decay, and the sum of neutrino masses in cosmology. In the limit of exactly degenerate…
At the Deep Underground Neutrino Experiment (DUNE), a proton beam hits a fixed target leading to large production rates of mesons. These mesons can decay and potentially provide a source of long-lived neutral fermions. Examples of such…
We develop the search strategy for a heavy Majorana neutrino via the lepton number violation signal process $p\, e^- \to \mu^+ jjj$ at future electron-proton colliders. The signal and dominant standard model background events are generated…
The Standard Model of particle physics (SM) is presently the best description of nature at small distances and high energies. However, with tiny but nonzero neutrino masses, a Higgs boson mass unstable under radiative corrections, and…
Long-lived light particles (LLLPs) appear in many extensions of the standard model. LLLPs are usually motivated by the observed small neutrino masses, by dark matter or both. Typical examples for fermionic LLLPs (a.k.a. heavy neutral…
It has been recently proposed that a sterile neutrino \nu_h of mass m_h=40--80 MeV, mixing |U_{\mu h}|^2=10^{-3}--10^{-2}, lifetime \tau_h \lsim 10^{-9} s, and a dominant decay mode (\nu_h \to \nu_\mu \gamma) could be the origin of the…
Neutrino masses can be generated by fermion triplets with TeV-scale mass, that would manifest at LHC as production of two leptons together with two heavy SM vectors or higgs, giving rise to final states such as 2 leptons + 4 jets (that can…
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…
The majoron, a neutrinophilic pseudo-Goldstone boson conventionally arising in the context of neutrino mass models, can damp neutrino free-streaming and inject additional energy density into neutrinos prior to recombination. The combination…
Low-scale seesaw variants protected by lepton number symmetry provide a natural explanation of the smallness of neutrino masses but, unlike their higher-scale counterparts, with potentially testable phenomenology. The approximate lepton…
Sterile neutrinos are SU(2) singlets that mix with active neutrinos via a mass matrix, its diagonalization leads to mass eigenstates that couple via standard model vertices. We study the cosmological production of heavy neutrinos via…
Next-generation large-volume detectors, such as GRAND, POEMMA, Trinity, TAROGE-M, TAMBO, or PUEO, have been designed to search for ultra-high-energy cosmic rays (UHECRs) with unprecedented sensitivity. We propose to use these detectors to…
In this brief review, I discuss the new physics unveiled by neutrino oscillation experiments over the past several years, and discuss several attempts at understanding the mechanism behind neutrino masses and lepton mixing. It is fair to…
It has been proposed that the coherent propagation of long-lived heavy neutrino mass eigenstates can lead to an oscillating rate of lepton number conserving (LNC) and violating (LNV) events, as a function of the distance between the…
We point out that the minimal seesaw model can provide a natural framework to accommodate tiny neutrino masses, while its experimental testability and notable predictiveness are still maintained. This possibility is based on the observation…
We investigate the reach at the LHC to probe light sterile neutrinos with displaced vertices. We focus on sterile neutrinos $N$ with masses $m_{N} \sim $ (5-30) GeV, that are produced in rare decays of the Standard Model gauge bosons and…
We examine in detail the neutrino masses and mixing patterns in an extension of the minimal supersymmetric standard model with three gauge-singlet neutrinos and R-parity violation. The Majorana masses for the gauge-singlet neutrinos as well…
This work explores the potential of the proposed FASER2 experiment at the LHC to determine the properties of a discovered heavy neutral lepton (HNL), including its mass, couplings, and whether it is a Majorana or Dirac fermion. We first…
We analyse two cases of the minimal extension of the Standard Model when one or two right-handed fields are added to the three left-handed fields. A second Higgs doublet (two Higgs doublet model - 2HDM) is included in our model. We…
We investigate the possibility of a fourth sequential generation in the lepton sector. Assuming neutrinos to be Majorana particles and starting from a recent - albeit weak - evidence for a non-zero admixture of a fourth generation neutrino…