Electroweak Baryogenesis from Exotic Electroweak Symmetry Breaking

TL;DR

This paper explores a novel two-stage electroweak phase transition involving an exotic scalar field, enabling baryogenesis while predicting new light particles accessible to experiments.

Contribution

It introduces a framework for electroweak baryogenesis via an exotic symmetry-breaking stage and provides an explicit model realization within the inert two Higgs doublet model.

Findings

A two-stage electroweak transition can generate baryon asymmetry.

The scenario predicts new light states testable experimentally.

The model decouples Higgs from the baryogenesis transition.

Abstract

We investigate scenarios in which electroweak baryogenesis can occur during an exotic stage of electroweak symmetry breaking in the early Universe. This transition is driven by the expectation value of a new electroweak scalar instead of the standard Higgs field. A later, second transition then takes the system to the usual electroweak minimum, dominated by the Higgs, while preserving the baryon asymmetry created in the first transition. We discuss the general requirements for such a two-stage electroweak transition to be suitable for electroweak baryogenesis and present a toy model that illustrates the necessary ingredients. We then apply these results to construct an explicit realization of this scenario within the inert two Higgs doublet model. Despite decoupling the Higgs from the symmetry-breaking transition required for electroweak baryogenesis, we find that this picture generically predicts new light states that are accessible experimentally.