A Cosmological Signature of the SM Higgs Instability: Gravitational Waves

TL;DR

This paper proposes that Higgs field fluctuations during inflation could produce detectable gravitational waves, offering a novel way to observe the Standard Model Higgs instability and its potential link to dark matter via primordial black holes.

Contribution

It provides a detailed characterization of gravitational waves sourced by Higgs fluctuations, linking collider physics, gravitational wave detection, and dark matter hypotheses.

Findings

Gravitational wave signals depend on Higgs and top masses.

LISA, Einstein Telescope, and Advanced LIGO could detect these signals.

The mechanism may also explain primordial black hole dark matter.

Abstract

A fundamental property of the Standard Model is that the Higgs potential becomes unstable at large values of the Higgs field. For the current central values of the Higgs and top masses, the instability scale is about $10^{11}$ GeV and therefore not accessible by colliders. We show that a possible signature of the Standard Model Higgs instability is the production of gravitational waves sourced by Higgs fluctuations generated during inflation. We fully characterise the two-point correlator of such gravitational waves by computing its amplitude, the frequency at peak, the spectral index, as well as their three-point correlators for various polarisations. We show that, depending on the Higgs and top masses, either LISA or the Einstein Telescope and Advanced-Ligo, could detect such stochastic background of gravitational waves. In this sense, collider and gravitational wave physics can provide fundamental and complementary informations. Furthermore, the consistency relation among the three- and the two-point correlators could provide an efficient tool to ascribe the detected gravitational waves to the Standard Model itself. Since the mechanism described in this paper might also be responsible for the generation of dark matter under the form of primordial black holes, this latter hypothesis may find its confirmation through the detection of gravitational waves.