Baryogenesis and Dark Matter in Multiple Hidden Sectors

TL;DR

This paper proposes a mechanism in models with multiple hidden sectors to generate baryon asymmetry and dark matter, predicting observable effects on cosmic microwave background measurements.

Contribution

It introduces a novel scenario where hidden sectors with varying Higgs masses produce dark matter and baryon asymmetry through a shared asymmetry transfer process.

Findings

Dark matter may form large dark nuclei.

Predicts a lower bound on $\

eff ext{ective } \

Abstract

We explore a mechanism for producing the baryon asymmetry and dark matter in models with multiple hidden sectors that are Standard-Model-like but with varying Higgs mass parameters. If the field responsible for reheating the Standard Model and the exotic sectors carries an asymmetry, it can be converted into a baryon asymmetry using the standard sphaleron process. A hidden sector with positive Higgs mass squared can accommodate dark matter with its baryon asymmetry, and the larger abundance of dark matter relative to baryons is due to dark sphalerons being active all the way down the hidden sector QCD scale. This scenario predicts that dark matter is clustered in large dark nuclei and gives a lower bound on the effective relativistic degrees of freedom, $\Delta N_{\rm eff} \gtrsim 0.05$, which may be observable in the next-generation cosmic microwave background experiment CMB-S4.