Related papers: Constraints on fourth generation Majorana neutrino…
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…
I analyze a fourth generation lepton sector in which the lightest particle is a stable Majorana neutrino. In this scenario fourth generation neutrinos have both a Dirac and Majorana mass, resulting in two Majorana neutrino mass eigenstates.…
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…
In extensions of the standard model with a heavy fourth generation one important question is what makes the fourth-generation lepton sector, particularly the neutrinos, so different from the lighter three generations. We study this question…
We reconsider the possibility that Majorana masses for the three known neutrinos are generated radiatively by the presence of a fourth generation and one right-handed neutrino with Yukawa couplings and a Majorana mass term. We find that the…
The production and decay of new possible heavy Majorana neutrinos are analyzed in hadronic collisions. New bounds on the mixing of these particles with standard neutrinos are estimated according to a fundamental representation suggested by…
We study the pair production of fourth generation neutrinos from the decay of an on-shell Higgs produced by gluon fusion. In a fourth generation scenario, the Higgs branching fraction into fourth generation neutrinos may be quite large. In…
We study the possibility of dark matter in the form of heavy neutrinos from a fourth lepton family with helicity suppressed couplings such that dark matter is produced thermally via annihilations in the early Universe. We present all…
The possibility of discovering heavy Majorana neutrinos and lepton number violation via the like sign dilepton signal at hadron super- colliders is investigated. The cross-sections for the production of these neutrinos singly as well as in…
We investigate the production of fourth generation neutrino in the context of new $e \nu_4 W$ magnetic dipole moment type interaction in $ep$ collisions at the future lepton-hadron colliders. We have obtained the mass limits of 700 GeV for…
The Majorana nature of neutrinos may only be experimentally verified via lepton-number violating processes involving charged leptons. We explore the $\Delta L=2$ like-sign dilepton production at hadron colliders to search for signals of…
We have studied the radiative corrections from the fourth generation leptons in the context of the see-saw mechanism. We have estimated numerically the differential cross section for the process (${\rm e}^{+}{\rm e}^{-}\! \rightarrow {\rm…
The Majorana nature of neutrinos can be experimentally verified only via {\it lepton-number} violating processes involving charged leptons. We study 36 lepton-number violating ($\lv$) processes from the decays of tau leptons and…
A study on the possibility of distinguishing new heavy Majorana neutrino models at LHC energies is presented. The experimental confirmation of standard neutrinos with non-zero mass and the theoretical possibility of lepton number violation…
We study the four-body heavy baryon decay, including two leptons in the final state, of the form $B_A \to B_B P \ell_\alpha \ell_\beta$, which can be either a lepton number conserving (LNC) or a lepton number violating (LNV) process (where…
Searches of lepton-number violation in different processes are very useful to constrain the parameter space of Majorana neutrinos. Here we use available upper bounds on the branching fractions of B^- -> D^0pi^+mu^-mu^- and D^0 ->…
Neutrino masses could originate in seesaw models testable at colliders, with light mediators and an approximate lepton number symmetry. The minimal model of this type contains two quasi-degenerate Majorana fermions forming a pseudo-Dirac…
We discuss the prospects of studying lepton number violating processes in order to identify Majorana neutrinos from low scale seesaw mechanisms at lepton-proton colliders. In particular, we consider the scenarios of colliding electrons with…
We investigate the sensitivity of some weak processes to the simplest extension of the Standard Model with Majorana neutrinos mixing in the leptonic sector. Values for mixing angles and masses compatible with several experimental…
The existence of Majorana neutrinos must lead to lepton-number violating processes, and the Majorana nature of neutrinos can only be experimentally verified via lepton-number violating processes. We propose a new approach to search for…