Vacuum Stability in the Standard Model and Beyond

TL;DR

This paper analyzes the stability of the Standard Model vacuum using high-order perturbation theory, examines the impact of input parameter uncertainties, explores extensions with scalar fields, and discusses collider phenomenology of potential new physics.

Contribution

It provides a comprehensive assessment of SM vacuum stability with updated parameters and explores the parameter space of scalar extensions, including collider phenomenology implications.

Findings

Vacuum stability depends critically on top mass and strong coupling.

Reducing uncertainties in these parameters can confirm or refute stability at 5σ.

Scalar extensions can stabilize the vacuum and have detectable collider signatures.

Abstract

We revisit the stability of the Standard Model vacuum, and investigate its quantum effective potential using the highest available orders in perturbation theory and the most accurate determination of input parameters to date. We observe that the stability of the electroweak vacuum centrally depends on the values of the top mass and the strong coupling constant. We estimate that reducing their uncertainties by a factor of two to three is sufficient to establish or refute SM vacuum stability at the $5\sigma$ level. We further investigate vacuum stability for a variety of singlet scalar field extensions with and without flavor using the Higgs portal mechanism. We identify the BSM parameter spaces for stability and find sizable room for new physics. We further study the phenomenology of Planck-safe models at colliders, and determine the impact on the Higgs trilinear, the Higgs-to-electroweak-boson, and the Higgs quartic couplings, some of which can be significant. The former two can be probed at the HL-LHC, the latter requires a future collider with sufficient energy and precision such as the FCC-hh.