Electroweak baryogenesis and gravitational waves in a composite Higgs model with high dimensional fermion representations

TL;DR

This paper explores electroweak baryogenesis within a composite Higgs model featuring high-dimensional fermion representations, demonstrating the potential for a strong first-order phase transition and detectable gravitational wave signals.

Contribution

It introduces a novel composite Higgs model with specific fermion embeddings that can produce a strong first-order electroweak phase transition and sufficient CP violation for baryogenesis.

Findings

Resonance masses around 1-10 TeV can induce SFOEWPT.

The model's CP violation explains the observed baryon asymmetry.

Predicted gravitational wave signals are detectable by future space-based detectors.

Abstract

We study electroweak baryogenesis in the $SO(6)/SO(5)$ composite Higgs model with the third generation quarks being embedded in the $\textbf{20}'$ representation of $SO(6)$. The scalar sector contains one Higgs doublet and one real singlet, and their potential is given by the Coleman-Weinberg potential evaluated from the form factors of the lightest vector and fermion resonances. We show that the resonance masses at $\mathcal{O}(1\sim 10{\rm ~TeV})$ can generate a potential that triggers the strong first-order electroweak phase transition (SFOEWPT). The $CP$ violating phase arising from the dimension-6 operator in the top sector is sufficient to yield the observed baryon asymmetry of the universe. The SFOEWPT parameter space is detectable at the future space-based detectors.