Baryogenesis from a dark first-order phase transition

TL;DR

This paper proposes a minimal dark sector model where a first-order phase transition generates baryon asymmetry, predicts detectable cosmological signals, and suggests potential collider and gravitational wave signatures.

Contribution

It introduces a new dark $SU(2)_D$ gauge model with specific particle content that facilitates baryogenesis and predicts observable effects in future experiments.

Findings

Predicts $ riangle N_{eff}$ between 0.09 and 0.13 detectable by future experiments.

Suggests possible signals from exotic Higgs and Z boson decays.

Forecasts stochastic gravitational wave signals from the phase transition.

Abstract

We present a very minimal model for baryogenesis by a dark first-order phase transition. It employs a new dark $SU(2)_{D}$ gauge group with two doublet Higgs bosons, two lepton doublets, and two singlets. The singlets act as a neutrino portal that transfer the generated asymmetry to the Standard Model. The model predicts $\Delta N_\text{eff} = 0.09-0.13$ detectable by future experiments as well as possible signals from exotic decays of the Higgs and $Z$ bosons and stochastic gravitational waves.