In this lecture I review the most relevant modifications of the Standard Model of particle physics that result from inclusion of right-handed neutrinos and a new neutral gauge boson Z.
In this article we consider the Standard Model extended by a number of (light) right-handed neutrinos, and assume the presence of some heavy physics that cannot be directly produced, but can be probed by its low-energy effective interactions. Within
this scenario, we obtain all the gauge-invariant dimension-seven effective operators, and determine whether each of the operators can be generated at tree-level by the heavy physics, or whether it is necessarily loop generated. We then use the tree-generated operators, including those containing right-handed neutrinos, to put limits on the scale of new physics $ Lambda $ using low-energy measurements. We also study the production of same-sign dileptons at the Large Hadron Collider (LHC) and determine the constraints on the heavy physics that can be derived form existing data, as well as the reach in probing $ Lambda $ expected from future runs of this collider.
The electron and muon number violating muonium-antimuonium oscillation process in an extended Minimal Supersymmetric Standard Model is investigated. The Minimal Supersymmetric Standard Model is modified by the inclusion of three right-handed neutrino
superfields. While the model allows the neutrino mass terms to mix among the different generations, the sneutrino and slepton mass terms have only intra-generation lepton number violation but not inter-generation lepton number mixing. So doing, the muonium-antimuonium conversion can then be used to constrain those model parameters which avoid further constraint from the $muto egamma$ decay bounds. For a wide range of parameter values, the contributions to the muonium-antimuonium oscillation time scale are at least two orders of magnitude below the sensivity of current experiments. However, if the ratio of the two Higgs field VEVs, $tanbeta$, is very small, there is a limited possibility that the contributions are large enough for the present experimental limit to provide an inequality relating $tanbeta$ with the light neutrino mass scale $m_ u$ which is generated by see-saw mechanism. The resultant lower bound on $tanbeta$ as a function of $m_ u$ is more stringent than the analogous bounds arising from the muon and electron anomalous magnetic moments as computed using this model.
Several models of neutrino masses predict the existence of neutral heavy leptons. Here, we review current constraints on heavy neutrinos and apply a new formalism separating new physics from Standard Model. We discuss also the indirect effect of extra heavy neutrinos in oscillation experiments.
In this paper we discuss the consequences of including a new heavy right-handed neutrino singlet $N_R$ in the littlest Higgs model. This new state is not connected with the light neutrinos {it via} the seesaw mechanism. A very interesting property of
this extended model is the full coupling of the new neutral gauge boson $A_H$ to $N_R$, giving large total cross sections and suggesting a wide range of experimental search for the $N_R$ at the p p collider CERN-LHC and future electron-positron collider ILC.
We consider right-handed neutrino pair production in generic $Z^prime$ models. We propose a new, model-independent analysis using final states containing a pair of same-sign muons. A key aspect of this analysis is the reconstruction of the RH neutrin
o mass, which leads to a significantly improved sensitivity. Within the $U(1)_{(B-L)_{3}}$ model, we find that at the HL-LHC it will be possible to probe RH neutrino masses in the range $0.2lesssim M_{N_R} lesssim 1.1,$TeV.