Superheavy Dark Matter from Thermal Inflation
  It is quite plausible that the mass of the dark matter particle increases significantly after its freeze-out, due to a scalar field rolling to large values. We describe a realization of this scenario in the context of thermal inflation which naturally gives a cold dark matter particle with the correct cosmological abundance and a mass around $10^{10} {\rm GeV}$, evading the conventional upper bound of $10^5 {\rm GeV}$. We also discuss another realization which could produce a cosmologically interesting abundance of near Planck mass, possibly electromagnetically charged, particles. The detection and observational consequences of superheavy cold dark matter or WIMPZILLAs are briefly examined. 
Lam Hui and Ewan D. Stewart (Fermilab)