Electroweak Baryogenesis in Non-minimal Composite Higgs Models

TL;DR

This paper explores how non-minimal composite Higgs models with a light singlet scalar can facilitate electroweak baryogenesis by enabling a strong first-order phase transition and new CP violation sources, aligning with experimental constraints.

Contribution

It demonstrates that composite Higgs models with a light singlet scalar can naturally support electroweak baryogenesis through phase transition dynamics and CP violation mechanisms.

Findings

Light singlet scalar induces strong first-order phase transition.

New CP violation sources from dimension-five operators.

Model consistent with experimental baryon asymmetry constraints.

Abstract

We address electroweak baryogenesis in the context of composite Higgs models, pointing out that modifications to the Higgs and top quark sectors can play an important role in generating the baryon asymmetry. Our main observation is that composite Higgs models that include a light, gauge singlet scalar in the spectrum [as in the model based on the symmetry breaking pattern SO(6)/SO(5)], provide all necessary ingredients for viable baryogenesis. In particular, the singlet leads to a strongly first-order electroweak phase transition and introduces new sources of CP violation in dimension-five operators involving the top quark. We discuss the amount of baryon asymmetry produced and the experimental constraints on the model.