Vacuum stability constraints on the minimal singlet TeV seesaw model

Abstract

We consider the minimal seesaw model in which two gauge singlet right handed neutrinos with opposite lepton numbers are added to the Standard Model. In this model, the smallness of the neutrino mass is explained by the tiny lepton number violating coupling between one of the singlets with the standard left-handed neutrinos. This allows one to have the right handed neutrino mass at the TeV scale as well as appreciable mixing between the light and heavy states. This model is fully reconstructible in terms of the neutrino oscillation parameters apart from the overall coupling strengths. We show that the overall coupling strength yν for the Dirac type coupling between the left handed neutrino and one of the singlets can be restricted by consideration of the (meta)stability bounds on the electroweak vacuum. In this scenario the lepton flavor violating decays of charged leptons can be appreciable which can put further constraint on yν, for right-handed neutrinos at TeV scale. We discuss the combined constraints on yν for this scenario from the process µ → eγ and from the consideration of vacuum (meta)stability constraints on the Higgs self coupling. We also briefly discuss the implications for neutrinoless double beta decay and possible signatures of the model that can be expected at colliders. The phase factor, e i π 2 , is inserted to ensure the positive definiteness of the mass eigen values.

Study of electroweak vacuum metastability with a singlet scalar dark matter

“…Vacuum metastability constraints in the context of seesaw models have been discussed in Refs. [14,23]. Planck scale dynamics is expected to affect the stability of EW vacuum.…”

Two component dark matter with inert Higgs doublet: neutrino mass, high scale validity and collider searches

“…Among these, type-I seesaw is the simplest possibility [54,55], which indicates the presence of heavy right handed (RH) neutrinos to yield correct light neutrino mass through additional Yukawa coupling with SM Higgs. This in turn may alter the Higgs vacuum stability condition at high scale (larger than the RH neutrino masses) with large neutrino Yukawa coupling [56][57][58][59][60][61][62][63][64][65][66][67][68]. Inclusion of an inert Higgs doublet along with right handed neutrinos can also generate the light neutrino mass radiatively [69].…”

On the stability of the electroweak vacuum in the presence of low-scale seesaw models

“…As already clear from these introductory comments, low-scale seesaw models may alter the metastability of the EW vacuum since they feature, at the same time, sizable Yukawa couplings and relatively low mass thresholds [50][51][52]. In this work we study in detail the stability of the EW vacuum considering the so-called inverse seesaw model (ISS) [44,45] as a reference model with low-scale seesaw.…”