Electroweak baryogenesis and gravitational waves from a real scalar singlet

TL;DR

This paper explores how a real scalar singlet can enable electroweak baryogenesis and produce detectable gravitational waves, linking particle physics with cosmological signals and testing new physics models.

Contribution

It demonstrates the potential of gravitational wave observations to probe electroweak baryogenesis models involving a scalar singlet and high-scale new physics.

Findings

Future gravitational wave detectors can test baryogenesis scenarios.

The model links strong first-order phase transition to observable gravitational waves.

Baryon-to-entropy ratio can be achieved even with high new physics scale.

Abstract

We consider a real scalar singlet field which provides a strong first-order electroweak phase transition via its coupling to the Higgs boson, and gives a $CP$ violating contribution on the top quark mass via a dimension-6 operator. We study the correlation between the baryon-to-entropy ratio produced by electroweak baryogenesis, and the gravitational wave signal from the electroweak phase transition. We show that future gravitational wave experiments can test, in particular, the region of the model parameter space where the observed baryon-to-entropy ratio can be obtained even if the new physics scale, which is explicit in the dimension-6 operator, is high.