Cosmological Time Evolution of the Higgs Mass and Gravitational Waves

TL;DR

This paper explores how gravitational wave detectors like LISA could detect a historical change in the Higgs boson’s self-coupling, indicating a varying Higgs mass and potentially revealing new physics beyond the Standard Model.

Contribution

It proposes that gravitational wave observations can probe the cosmological evolution of the Higgs self-coupling and mass, linking gravitational wave signals to early universe phase transitions.

Findings

LISA could detect gravitational waves from the electroweak phase transition.

A stochastic gravitational wave background may indicate a smaller Higgs self-coupling in the past.

Detection of such waves could suggest new physics beyond the Standard Model.

Abstract

We point out that gravitational wave detectors such as LISA have the potential of probing a cosmological time evolution of the Higgs boson self-coupling constant $\lambda$ and thus the Higgs boson's mass $m_H= \sqrt{ 2 \lambda} v$. The phase transition of the Standard Model could have been a first order one if the Higgs mass was below 72 GeV at a temperature $T_\star \ge 100$ GeV. Gravitational waves could thus have been produced during the electroweak phase transition. A discovery by LISA of a stochastic background of gravitational waves with a characteristic frequency $k_\star \ge 10^{-5}$ Hz could be interpreted as a sign that the Higgs boson self-coupling constant was smaller in the past. This interpretation would be particularly tempting if the Large Hadron Collider did not discover any physics beyond the Standard Model by the time such waves are seen. The same mechanism could also account for baryogenesis.