Electroweak vacuum metastability in a natural minimal type-III seesaw model

Abstract

We study the minimal type-III seesaw model in which we extend the SM by adding two SU (2) L triplet fermions with zero hypercharge to explain the origin of the non-zero neutrino masses and mixing. We show that the naturalness conditions and the limits from lepton flavor violating decays provide very stringent bounds on the model along with the constraints on the stability/metastability of the electroweak vacuum. We perform a detailed analysis of the model parameter space including all the constraints for both normal as well as inverted hierarchies of the light neutrino masses. We find that most of the region that are allowed by lepton flavor violating decay and naturalness fall in the metastable region.