Universal gravitational-wave signatures from heavy new physics in the electroweak sector

TL;DR

This paper calculates gravitational-wave spectra from the electroweak phase transition with TeV-scale new physics, revealing a universal relation that helps distinguish heavy from light new physics and guides future observational efforts.

Contribution

It introduces a universal relation between bubble separation and phase transition strength applicable to various new physics models, aiding in gravitational-wave spectrum predictions.

Findings

Universal relation between bubble separation and phase transition strength.

Constraints on gravitational-wave signals from heavy new physics.

Potential to differentiate heavy and light new physics via gravitational waves.

Abstract

We calculate the gravitational-wave spectra produced by the electroweak phase transition with TeV-scale Beyond-Standard-Model physics in the early universe. Our study captures the effect of quantum and thermal fluctuations within a non-perturbative framework. We discover a universal relation between the mean bubble separation and the strength parameter of the phase transition, which holds for a wide range of new-physics contributions. The ramifications of this result are three-fold: First, they constrain the gravitational-wave spectra resulting from heavy (TeV-scale) new physics. Second, they contribute to distinguishing heavy from light new physics directly from the gravitational-wave signature. Third, they suggest that a concerted effort of gravitational-wave observations together with collider experiments could be required to distinguish between different models of heavy new physics.