QCD Baryogenesis
  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.
