Superheavy dark matter in $R+R^2$ cosmology with conformal anomaly
  Cosmological evolution and particle creation in $R^2$-modified gravity are
considered for the case of the dominant decay of the scalaron into a pair of
gauge bosons due to conformal anomaly. It is shown that in the process of
thermalization superheavy dark matter with the coupling strength typical for
the GUT SUSY can be created. Such dark matter would have the proper
cosmological density if the particle mass is close to $10^{12}$ GeV.
