Vacuum Stability and Radiative Symmetry Breaking of the Scale-Invariant Singlet Extension of Type II Seesaw Model

TL;DR

This paper investigates how radiative symmetry breaking can occur in a scale-invariant singlet extension of the type II seesaw model, addressing electroweak symmetry and neutrino mass origins with new scalar potential analysis.

Contribution

It derives the first comprehensive bounded-from-below conditions for the scalar potential and explores parameter space for radiative electroweak symmetry breaking at one-loop level.

Findings

Heavy triplet-like Higgs bosons are nearly degenerate in mass.

The Higgs quartic coupling can remain positive up to the Planck scale.

Parameter space consistent with collider constraints is identified.

Abstract

The questions of the origin of electroweak symmetry breaking and neutrino mass are two major puzzles in particle physics. Neutrino mass generation requires new physics beyond the Standard Model and also suggests reconsideration of physics of symmetry breaking. The aim of this paper is to study radiative symmetry breaking in the singlet scalar extension of type II seesaw neutrino mass model. We derive bounded-from-below conditions for the scalar potential of the model in full generality for the first time. The Gildener-Weinberg approach is utilised in minimising the multiscalar potential. Upon imposing the bounded-from-below and perturbativity conditions, as well as experimental constraints from colliders, we find the parameter space of scalar quartic couplings that can radiatively realise electroweak symmetry breaking at one-loop level. To satisfy all the constraints, the masses of the heavy triplet-like Higgs bosons must be nearly degenerate. The evolution of the Higgs doublet quartic coupling $\lambda_{H}$ can be prevented from being negative up to the Planck scale.