Scale genesis and gravitational wave in a classically scale invariant extension of the standard model

TL;DR

This paper proposes a model where the electroweak scale arises from a strongly interacting gauge sector, leading to a first-order phase transition that generates a gravitational wave background detectable by DECIGO.

Contribution

It introduces a classically scale-invariant extension of the Standard Model with a gauge-invariant scalar-bilinear condensation mechanism for scale genesis, linking it to gravitational wave production.

Findings

The scale phase transition occurs above the electroweak transition temperature.

The phase transition is strongly first-order, producing a detectable gravitational wave background.

The predicted gravitational wave spectrum is within DECIGO's observational sensitivity.

Abstract

We assume that the origin of the electroweak (EW) scale is a gauge-invariant scalar-bilinear condensation in a strongly interacting non-abelian gauge sector, which is connected to the standard model via a Higgs portal coupling. The dynamical scale genesis appears as a phase transition at finite temperature, and it can produce a gravitational wave (GW) background in the early Universe. We find that the critical temperature of the scale phase transition lies above that of the EW phase transition and below few $O(100)$ GeV and it is strongly first-order. We calculate the spectrum of the GW background and find the scale phase transition is strong enough that the GW background can be observed by DECIGO.