Nonthermal Supermassive Dark Matter

We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may be elementary particles of mass much greater than the weak scale. Searches for dark matter should not be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well. [S0031-9007(98)07529-2] PACS numbers: 95.35. + d, 98.80.Cq There is conclusive evidence that the dominant component of the matter density in the Universe is dark. The most striking indication of the existence of dark matter (DM) is the observations of flat rotation curves for spiral galaxies [1], indicating that DM in galactic halos is about 10 times more abundant than the luminous component. Dynamical evidence for DM in clusters of galaxies is also compelling. In terms of the critical density, rC › 3H 2 0 M