This week it was announced that a dark matter detector about 700 meters below the ground in a Minnesota mine has recorded a seasonal modulation in staggeringly faint electrical pulses. One possible reason: this could be the result of dark matter particles called WIMPs that envelope the Milky Way galaxy and collide with atoms in the detector’s germanium crystal. This seems possible because the results are consistent with modulation in signals first recorded more than a decade ago by the DArk MAtter/Large sodium Iodide Bulk for RAre processes (DAMA/LIBRA) experiment at Gran Sasso, Italy. It also appears to match recent but as-yet-unpublished findings by another experiment called CRESST, or the Cryogenic Rare Event Search with Superconducting Thermometers, also at Gran Sasso.
The findings, by the Coherent Germanium Neutrino Technology [CoGeNT] experiment, are described in a paper posted online by a team of researchers led by Juan Collar of the Kavli Institute for Cosmological Physics at the University of Chicago. While Collar and his colleagues emphasize that the origin of the signals is unknown, the data collected from 442 days of observations are, according to Collar, “prima facie congruent when the WIMP hypothesis is examined.” Said Collar, “[It] gives you pause, the fact that the same kind of dark matter particle could be behind these three different observations from three very different detectors.”