Trans-planckian wimpzillas

Two previously proposed conjectures-gravitational trans-Planckian particle creation in the expanding universe, and the existence of ultraheavy stable particles with masses up to the Planck scale (wimpzillas)-are combined in a proposal for trans-Planckian particle creation of wimpzillas. This new scenario leads to a huge enhancement in their production compared to mechanisms put forward earlier. As a result, it requires the trans-Planckian particle creation parameter to be rather small to avoid overproduction of such particles, much less than that required for observable effects in the primordial perturbation spectrum. This ensures also that wimpzillas are mainly created at the end of primordial in. flation. Conditions under which trans-Planckian wimpzillas can constitute the present dark matter are determined.