The detection of dark matter particles, named WIMPs (weakly interacting massive particles), is an endeavor occupying many researchers. Though there is ample indirect evidence suggesting that nearly a quarter of the universe is made up of this mysterious substance, it has yet to be observed directly. Since the Milky Way, like all other galaxies, is nestled in a dark matter halo, researchers hope to capture collisions between WIMPs and atoms in detectors.
Recent calibration runs using new PICASSO detectors suggest such suppression is possible. This stems form the fact that the interactions’ acoustic signals contain information about the primary events, the alpha signals being more intense than those of the WIMPs. At present the cause of this difference is unknown, though one possible explanation has to do with the number of nucleation sites contributing to the signal.