Measuring gravitational wave spectrum from electroweak phase transition and Higgs self-couplings

TL;DR

This paper explores how space-based gravitational wave detectors can measure the stochastic background from electroweak phase transitions, constraining particle physics parameters like Higgs self-couplings.

Contribution

It demonstrates a complete process of parameter inference from simulated gravitational wave data, linking cosmological signals to particle physics parameters.

Findings

Gravitational wave spectra can constrain electroweak phase transition parameters.

Higgs self-couplings can be significantly constrained through gravitational wave observations.

Parameter degeneracies pose limitations but do not prevent meaningful constraints.

Abstract

In this work, we demonstrate the complete process of using space-based gravitational wave detectors to measure properties of the stochastic gravitational wave background arising from a first-order electroweak phase transition. Based on frequency-domain simulations of the Taiji mission, including instrumental noise and astrophysical foregrounds, we perform parameter inference using both the Fisher information matrix and Bayesian Markov Chain Monte Carlo sampling. We show how the reconstructed spectrum constrains the macroscopic parameters of the phase transition, and further how these constraints map onto the underlying particle-physics parameters in a singlet-extended Standard Model. Our results demonstrate that the Higgs cubic and quartic self-couplings can be significantly constrained using gravitational wave observations, despite limitations arising from parameter degeneracy.