If neutrino masses are realized through the see-saw mechanism, can the right-handed neutrinos be produced and detected at present and future colliders? A model of electroweak-scale right-handed neutrino (EW$\nu_R$) model was constructed six years ago, in which the right-handed neutrinos are members of mirror fermion weak doublets and where the Majorana masses of the right-handed neutrinos are found to be naturally of the order of the electroweak scale [P.Q.Hung, Phys. Lett. B. 249 (2007)]. These features facilitate their searches at the LHC through signals such as like-sign dilepton events. This model contains, in addition to the mirror quarks and leptons, extra scalars transforming as weak triplets. We have studied the constraints imposed on these additional particles by the electroweak precision parameters S, T, and U [[hep-ph]arXiv:1303.0428v2]. These constraints are crucial in determining the viability of the electroweak $\nu_R$ model and the allowed parameter space needed for a detailed phenomenology of the model. This parameters space in EW$\nu_R$ model is made of masses of the mirror fermions, masses of the physical states of the weak scalars and the mixing between weak scalar doublet and triplets. Our analysis concludes that there is, indeed, a part of the total parameter space of this model, which agrees with the experimental constraints on these electroweak precision parameters.
Furthermore, in a simple extension of EW$\nu_R$ model, a light 0+ physical scalar (which we call $H_1^L$) arises in the mass range of 126 GeV, which can have its production rates through gluon-gluon fusion similar to that of the Standard Model Higgs boson. This physical scalar can also have total decay rates of $H_1^L$ -> ZZ, WW and \gamma\gamma similar to the measured decay rates of the newly discovered Standard Model-like Higgs particle at the LHC.