Gravitationally produced Top Quarks and the Stability of the Electroweak Vacuum During Inflation

TL;DR

This paper investigates how gravitationally produced top quarks during inflation influence the Higgs potential, affecting the stability of the electroweak vacuum in the early universe within the Standard Model framework.

Contribution

It introduces a novel analysis of top quark production during inflation and its impact on Higgs vacuum stability using minimal coupling and general relativity.

Findings

Top quark production significantly affects Higgs potential near the stability scale.

The effect is negligible for inflation scales below the stability threshold.

Other fermions' contributions to Higgs instability are briefly discussed.

Abstract

In the standard model the (Brout-Englert-)Higgs quartic coupling becomes negative at high energies rendering our current electroweak vacuum metastable, but with an instability timescale much longer than the age of the Current Universe. During cosmological Inflation, unless there is a non-minimal coupling to gravity, the Higgs field is pushed away from the origin of its potential due to quantum fluctuations. It is therefore a mystery how we have remained in our current vacuum if we went through such a period of Inflation. In this work we study the effect of top quarks created gravitationally during Inflation and their effect upon the Higgs potential using only General Relativity with minimal couplings and Standard Model particle physics. We show how the evolution of the Higgs field during Inflation is modified coming to the conclusion that this effect is non negligible for scales of Inflation close to or larger than the stability scale but small for scales where the Higgs is stable. Also, we briefly discuss the effect of other fermions to the Higgs instability.