Standard Model vacuum decay in a de Sitter Background

TL;DR

This paper calculates vacuum decay solutions in the Standard Model within a de Sitter universe, revealing multiple solutions and emphasizing the need for further understanding of their implications for vacuum stability.

Contribution

It provides the first detailed analysis of thick-wall Coleman-de-Luccia bounce solutions with full metric back-reaction in the Standard Model potential.

Findings

Multiple bounce solutions exist beyond the dominant one.

Additional solutions have higher actions and minimal impact on decay rate.

Standard Model CdL solutions are not unique, affecting vacuum decay interpretations.

Abstract

We present a calculation of thick-wall Coleman-de-Luccia (CdL) bounces in the Standard Model effective potential in a de Sitter background. The calculation is performed including the effect of the bounce back-reaction on the metric, which we compare with the case of a fixed de-Sitter background, and with similar full-backreaction calculation in a model polynomial potential. The results show that the Standard Model potential exhibits non-trivial behavior: rather than a single CdL solution, there are multiple (non-oscillating) bounce solutions which may contribute to the decay rate. All the extra solutions found have higher actions than the largest amplitude solution, and thus would not contribute significantly to the decay rate, but their existence demonstrates that CdL solutions in the Standard Model potential are not unique, and the existence of additional, lower action, solutions cannot be ruled out. This suggests that a better understanding of the appearance and disappearance of CdL solutions in de Sitter space is needed to fully understand the vacuum instability issue in the Standard Model.