Laboratory limits on galactic cold dark matter

Interesting limits are set on candidates for cold-dark matter particles in the halo of the Galaxy from their interaction with a very-low-background Ge detector used to search for double-beta decay. Dirac neutrinos constituting all of dark matter are excluded for masses between 12 GeV/c- squared and 1.4 TeV /c-squared. There are slightly better limits on magninos and cosmions, proposed massive particles which also explain the solar-neutrino problem but which interact more strongly with Ge. In addition, millicharged shadow matter is ruled out as the main form of dark matter. (Author)