Non-sterile electroweak-scale right-handed neutrinos and the dual nature of the 125-GeV scalar

Abstract

Can, and under which conditions, the 125-GeV SM-like scalar with the signal strengths for its decays into W + W − , ZZ, γ γ , bb and ττ being consistent with experiments be accommodated in models that go beyond the Standard Model? Is it truly what it appears to be, namely the SM Higgs boson, or could it be quite different? A minimal extension of the original electroweak-scale right-handed neutrino model, in which right-handed neutrinos naturally obtain electroweak-scale masses, shows a scalar spectrum which includes either the 125-GeV SM-like scalar or a scalar which is quite unlike that of the Standard Model, both of which possess signal strengths compatible with experiment. In other words, the 125-GeV scalar could be an impostor.

Search for electroweak-scale right-handed neutrinos and mirror charged leptons through like-sign dilepton signals

“…In the present absence of such quantities, the best one can do is to present cases which are consistent with the experimental signal strengths. This is what was carried out in [15].…”

“…As shown in [9] and in the extension of the EW-scale ν R model [15], SM quarks and charged leptons obtain masses by coupling to the doublet Φ 2 and mirror quarks and charged leptons obtain theirs by coupling to Φ 2M .…”

“…An extended version was proposed [15] in order to accommodate the 125-GeV SM-like scalar and, in this version, Φ 2 only couples to SM fermions while another doublet Φ 2M whose VEV is φ 0 2M = v 2M / √ 2 couples only to mirror fermions.…”

“…LIGHT OF THE DISCOVERY OF THE 125-GEV SM-LIKE SCALAR [15] In light of the discovery of the 125-GeV SM-like scalar, it is imperative that any model beyond the SM (BSM) shows a scalar spectrum that contains at least one Higgs boson. The definition of a signal strength µ is as follows…”

“…The minimization of the potential containing the scalars shown above breaks its global symmetry SU (2) L × SU (2) R down to a custodial symmetry SU (2) D which guarantees at tree level ρ = M 2 W /M 2 Z cos 2 θ W = 1 [15]. The physical scalars can be grouped, based on their transformation properties under SU (2) D as follows:…”