Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

On Stability of the Electroweak Vacuum and the Higgs Portal

Oleg Lebedev

TL;DR

The paper investigates a SM extension with a singlet scalar coupled via the Higgs portal to address electroweak vacuum stability.It demonstrates that even with vanishing Higgs–singlet mixing, a tree-level correction to the Higgs mass–coupling relation can stabilize the potential, provided $\\lambda_{hs}^2/(4 \\\lambda_s) \\gtrsim 0.015$ for a TeV-scale singlet.The scenario remains practically SM-like at low energies, with potential modifications to the Higgs self-coupling offering a measurable signature at future colliders.The framework also preserves Higgs portal inflation, either through a large non-minimal coupling with a mixed inflaton or via singlet-induced loop stabilization, broadening the space of viable inflationary models.

Abstract

In the Standard Model (SM), the Higgs mass around 125 GeV implies that the electroweak vacuum is metastable since the quartic Higgs coupling turns negative at high energies. I point out that a tiny mixing of the Higgs with a heavy singlet can make the electroweak vacuum completely stable. This is due to a tree level correction to the Higgs mass-coupling relation, which survives in the zero-mixing/heavy-singlet limit. Such a situation is experimentally indistinguishable from the SM, unless the Higgs self-coupling can be measured. As a result, Higgs inflation and its variants can still be viable.

On Stability of the Electroweak Vacuum and the Higgs Portal

TL;DR

The paper investigates a SM extension with a singlet scalar coupled via the Higgs portal to address electroweak vacuum stability.It demonstrates that even with vanishing Higgs–singlet mixing, a tree-level correction to the Higgs mass–coupling relation can stabilize the potential, provided $\\lambda_{hs}^2/(4 \\\lambda_s) \\gtrsim 0.015$ for a TeV-scale singlet.The scenario remains practically SM-like at low energies, with potential modifications to the Higgs self-coupling offering a measurable signature at future colliders.The framework also preserves Higgs portal inflation, either through a large non-minimal coupling with a mixed inflaton or via singlet-induced loop stabilization, broadening the space of viable inflationary models.

Abstract

In the Standard Model (SM), the Higgs mass around 125 GeV implies that the electroweak vacuum is metastable since the quartic Higgs coupling turns negative at high energies. I point out that a tiny mixing of the Higgs with a heavy singlet can make the electroweak vacuum completely stable. This is due to a tree level correction to the Higgs mass-coupling relation, which survives in the zero-mixing/heavy-singlet limit. Such a situation is experimentally indistinguishable from the SM, unless the Higgs self-coupling can be measured. As a result, Higgs inflation and its variants can still be viable.

Paper Structure

This paper contains 9 sections, 25 equations, 2 figures.

Table of Contents

  1. Introduction
  2. Higgs portal potential and stability
  3. Relevant formulae
  4. Large singlet VEV limit
  5. Numerical example
  6. Rescuing Higgs inflation
  7. The setup
  8. Singlet--assisted Higgs inflation
  9. Conclusion

Figures (2)

  • Figure 1: Higgs quartic coupling evolution with energy for various $\lambda_{hs}$ and $\lambda_s=0.01$ at $m_t$. The Higgs mass is fixed at approximately 125 GeV.
  • Figure 2: Parameter space allowed by Higgs inflation for the two vacua: $u \gg v$ (left) and $u=0$ (right). The Higgs mass is fixed at approximately 125 GeV and $\xi_s/\xi_h = 10^{-3}$.