  We propose a new mechanism for explaining the observed asymmetry between
matter and antimatter, based on nonperturbative physics at the QCD scale. Our
mechanism is a charge separation scenario, making use of domain walls
separating the recently discovered long-lived metastable vacua from the lowest
energy vacuum. The walls acquire a fractional negative baryon charge, leaving
behind a compensating positive baryon charge in the bulk. The regions of
metastable vacuum bounded by walls ("B-shells") will contribute to the dark
matter of the Universe.
