Neutrino Masses and Higgs Vacuum Stability

TL;DR

This paper explores how extensions of the Standard Model, specifically type-II seesaw and left-right symmetric models, can ensure Higgs vacuum stability and accommodate neutrino masses, addressing metastability issues.

Contribution

It demonstrates that viable left-right symmetric models can be constructed with stable Higgs vacuum by detailed renormalisation group analysis and threshold corrections.

Findings

Existence of large parameter space with absolute Higgs vacuum stability.

Viable left-right symmetric models constructed at one-loop level.

Vacuum stability achieved within extended models accommodating neutrino masses.

Abstract

The Standard Model electroweak vacuum has been found to be metastable, with the true stable vacuum given by a large, phenomenologically unacceptable vacuum expectation value $\approx M_{P}$. Moreover, it may be unstable in an inflationary universe. Motivated by the necessity of physics beyond the Standard Model and to accommodate non-zero neutrino masses, we investigate vacuum stability within type-II seesaw and left-right symmetric models. Our analysis is performed by solving the renormalisation group equations, carefully taking into account the relevant threshold corrections. We demonstrate that a phenomenologically viable left-right symmetric model can be constructed by matching it with the SM at one-loop. In both models we demonstrate the existence of a large area of parameter space where the Higgs vacuum is absolutely stable.