Signals of the electroweak phase transition at colliders and gravitational wave observatories

TL;DR

This paper investigates the electroweak phase transition's signals at colliders and gravitational wave observatories, emphasizing the importance of dimension-eight operators in effective field theory for accurate analysis.

Contribution

It extends the EFT analysis of the electroweak phase transition to include dimension-eight operators and compares collider and gravitational wave detection prospects.

Findings

LISA can probe regions with a strongly first order EWPT.

Double-Higgs production is less effective for detecting these scenarios.

Dimension-eight operators significantly impact EWPT analysis.

Abstract

If the electroweak phase transition (EWPT) is of strongly first order due to higher dimensional operators, the scale of new physics generating them is at the TeV scale or below. In this case the effective-field theory (EFT) neglecting operators of dimension higher than six may overlook terms that are relevant for the EWPT analysis. In this article we study the EWPT in the EFT to dimension eight. We estimate the reach of the future gravitational wave observatory LISA for probing the region in which the EWPT is strongly first order and compare it with the capabilities of the Higgs measurements via double-Higgs production at current and future colliders. We also match different UV models to the previously mentioned dimension-eight EFT and demonstrate that, from the top-down point of view, the double-Higgs production is not the best signal to explore these scenarios.