Production and evaporation of micro black holes as a link between mirror
  universes
  It is shown that the equalization of temperatures between our and mirror
sectors occurs during one Hubble time due to microscopic black hole production
and evaporation in particle collisions if the temperature of the Universe is
near the multidimensional Plank mass. This effect excludes the multidimensional
Planck masses smaller than the reheating temperature of the Universe
($\sim10^{13}$ GeV) in the mirror matter models, because the primordial
nucleosynthesis theory requires that the temperature of the mirror world should
be lower than ours. In particular, the birth of microscopic black holes in the
LHC is impossible if the dark matter of our Universe is represented by baryons
of mirror matter. It excludes some of the possible coexisting options in
particle physics and cosmology. Multidimensional models with flat additional
dimensions are already strongly constrained in maximum temperature due to the
effect of Kaluza-Klein mode (KK-mode) overproduction. In these models, the
reheating temperature should be significantly less than the multidimensional
Planck mass, so our restrictions in this case are not paramount. The new
constraints play a role in multidimensional models in which the spectrum of
KK-modes does not lead to their overproduction in the early Universe, for
example, in theories with hyperbolic additional space.
