Dark Matter via Many Copies of the Standard Model
  We propose a cosmological scenario based on the assumption that the Standard
Model possesses a large number of copies. It is demonstrated that baryons in
the hidden copies of the standard model can naturally account for the dark
matter. The right abundance of the hidden-sector baryons and the correct
spectrum of density perturbations are simultaneously generated during modulated
reheating. We show that for the natural values of inflaton coupling constants,
dictated by unitarity, the dark-matter abundance is predicted to be
proportional to the ratio of observed cosmological parameters: the square of
the amplitude of cosmological perturbations and the baryon-to-photon number
ratio.
