Direct detection constraints on superheavy dark matter.

The dark matter in the Universe might be composed of superheavy particles (mass greater, similar 10(10) GeV). These particles can be detected via nuclear recoils produced in elastic scatterings from nuclei. We estimate the observable rate of strongly interacting supermassive particles (simpzillas) in direct dark matter search experiments. The simpzilla energy loss in Earth and in the experimental shields is taken into account. The most natural scenarios for simpzillas are ruled out based on recent EDELWEISS and CDMS results. The dark matter can be composed of superheavy particles only if these interact weakly with normal matter or if their mass is above 10(15) GeV.

Neutrino telescopes as a direct probe of supersymmetry breaking.

We consider models where the scale of supersymmetry breaking lies between 5 x 10(6) and 5 x 10(8) GeV. In this class of theories, which includes models of mediated supersymmetry breaking, the lightest supersymmetric particle is the gravitino, and the next to lightest is typically a long-lived charged slepton with a lifetime between a microsecond and a second, depending on its mass. We investigate the production of these particles by the diffuse flux of high energy neutrinos colliding with nucleons in the Earth, and the potential for their observation in large ice or water Cerenkov detectors. The small production cross section is partially compensated by the very long range of sleptons. The signal, two well-separated parallel tracks, has very little background. Using the Waxman-Bahcall limit for the neutrino flux results in up to four events a year in km3 experiments.