Hints of BSM physics in the SM effective potential

TL;DR

This paper explores how modifications to the Standard Model effective potential at high field strengths can indicate new physics, analyzing vacuum stability and the impact of nonrenormalizable interactions on the electroweak vacuum's lifetime.

Contribution

It provides a detailed map of vacuum lifetimes with nonrenormalizable couplings and discusses gauge-invariant methods for calculating tunnelling rates.

Findings

Adding Planck-scale suppressed interactions generally shortens vacuum lifetime.

Lowering the suppression scale can stabilize the electroweak vacuum.

Gauge dependence issues in tunnelling rate calculations can be addressed at leading order.

Abstract

Investigation of the structure of the Standard Model effective potential at very large field strengths opens a window towards new phenomena and can reveal properties of the UV completion of the SM. The map of the lifetimes of the vacua of the SM enhanced by nonrenormalizable scalar couplings has been compiled to show how new interactions modify stability of the electroweak vacuum. Whereas it is possible to stabilize the SM by adding Planck scale suppressed interactions and taking into account running of the new couplings, the generic effect is shortening the lifetime and hence further destabilisation of the SM electroweak vacuum. Absolute stability can be achieved by lowering the suppression scale of higher order operators while picking up such combinations of new couplings, which do not generate new deep minima in the potential. We discuss the issue of gauge dependence of the perturbative determination of the tunnelling rate and show how this rate can be made gauge independent at the leading nontrivial order of the RGE improved effective action.