Interesting limits are set on candidates for cold-dark-matter particles in the halo of our 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/${\mathit{c}}^2$ and 1.4 TeV/${\mathit{c}}^2$. 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.

• Received 13 November 1987

DOI:https://doi.org/10.1103/PhysRevLett.61.510