QCD Baryogenesis

TL;DR

This paper presents a model where dynamical QCD confinement and electroweak symmetry breaking naturally generate the Universe's baryon asymmetry through spontaneous baryogenesis, with implications for collider and gravitational wave experiments.

Contribution

It introduces a novel model linking QCD confinement, axion dynamics, and baryogenesis, with detailed analysis of parameter space and experimental signatures.

Findings

Viable parameter regions for baryogenesis identified

Predictions for collider constraints and gravitational wave signals

Demonstrates spontaneous baryogenesis mechanism during QCD confinement

Abstract

We explore a simple model which naturally explains the observed baryon asymmetry of the Universe. In this model the strong coupling is promoted to a dynamical quantity, which evolves through the vacuum expectation value of a singlet scalar field that mixes with the Higgs field. In the resulting cosmic history, QCD confinement and electroweak symmetry breaking initially occur simultaneously close to the weak scale. The early confinement triggers the axion to roll toward its minimum, which creates a chemical potential between baryons and antibaryons through the interactions of the $\eta'$ meson, resulting in spontaneous baryogenesis. The electroweak sphalerons are sharply switched off after confinement and the baryon asymmetry is frozen in. Subsequently, evolution of the Higgs vacuum expectation value (which is modified in the confined phase) triggers a relaxation to a Standard Model-like vacuum. We identify viable regions of parameter space, and describe various experimental probes, including current and future collider constraints, and gravitational wave phenomenology.