Fate of Electroweak Vacuum during Preheating

TL;DR

This paper investigates whether Higgs-inflaton/-curvature coupling can prevent electroweak vacuum decay during preheating after inflation, by analyzing Higgs production and establishing bounds on the coupling strength.

Contribution

It provides a detailed analysis of Higgs production during preheating and derives upper bounds on the Higgs-inflaton/-curvature coupling to ensure vacuum stability.

Findings

Upper bounds on Higgs-inflaton/-curvature coupling established

Higgs fluctuations can destabilize the vacuum during preheating

Possible dynamics discussed that might relax stability bounds

Abstract

Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after the inflation, the additional mass term oscillates, and it can potentially destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum by properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton/-curvature coupling, and discuss possible dynamics that might relax them.