Unveiling New Phases of the Standard Model Higgs Potential

TL;DR

This paper uncovers new phases of the Standard Model Higgs potential, revealing unstable and stable phases at high energies, which influence the model's stability and potential ultraviolet completions.

Contribution

It identifies previously unknown phases of the Higgs potential using a mass-dependent functional renormalisation group approach, impacting Standard Model extrapolations and extensions.

Findings

Unstable and stable phases found above the Planck scale

New phases affect the metastability of the Standard Model

Implications for model building and ultraviolet completions

Abstract

We present evidence for new phases of the Standard Model Higgs potential. We study the Standard Model physical trajectory accounting for the Higgs curvature mass with the mass-dependent functional renormalisation group. New unstable and non-trivially stable phases are found at energies above the Planck scale and below the Abelian Landau pole. While the first aggravates the well-known metastable phase and threatens the viability of the Standard Model extrapolated to arbitrary scales, the latter can provide a well-defined ultraviolet completion. We investigate the phase diagram as a function of the top quark pole mass and study the effect of new physics through a scalar singlet portal coupling. The new non-trivial phase appears below the Planck scale in extensions of the Standard Model seeking stable trajectories. These findings have a significant impact on existing model building.