Probing the electroweak symmetry breaking history with Gravitational waves

TL;DR

This paper uses lattice simulations to analyze gravitational wave signals from a two-step electroweak symmetry breaking process, revealing distinct spectral signatures for different BSM scenarios, thus offering a new probe of early Universe physics.

Contribution

It introduces a detailed simulation-based analysis of gravitational waves from electroweak phase transitions, highlighting how different BSM mechanisms produce distinguishable gravitational wave spectra.

Findings

Broken power-law double-peak spectra for low-scale BSM scenarios

Plateau-shaped spectra from high-scale global U(1) phase transition

Gravitational waves can differentiate between BSM models of electroweak symmetry breaking

Abstract

We perform a three dimensional lattice simulation of the electroweak symmetry breaking process through a two-step phase transition, where one of the two steps is a first order phase transition. Our results show that: 1) when the electroweak symmetry breaking is driven by the beyond Standard Model sector around $\sim \mathcal{O}(10^{2-3})$ GeV, the gravitational wave spectra produced from the phase transitions are of broken power-law double-peak shapes; 2) when the electroweak symmetry breaking is induced by a first-order phase transition of a high-scale global U(1) theory, cosmic strings can form and then disappear through particle radiation, and the yielded gravitational wave spectra are of plateau shapes. The two scenarios can be distinguished through probing gravitational wave spectra. Our study suggests that the stochastic gravitational waves provide an alternative way to probe the beyond Standard Model sector relevant to the electroweak symmetry breaking pattern in the early Universe.