Dark Matter Search Goes Underground

From a vantage point a half-mile below ground, physicists of the Cryogenic Dark Matter Search have launched a quest to detect the dark matter that pervades the universe. Scientists of CDMS II, an experiment in the Soudan Iron Mine in northeastern Minnesota, hope to discover the weakly interacting massive particles that are leading candidates for the constituents of dark matter. The WIMPs are thought to be particles more massive than protons but interacting so rarely that thousands would pass through us undetected each second. Only occasionally would a WIMP hit a terrestrial atom, leaving a signal in the CDMS II detector.

In the kind of convergence that gets physicists' attention, the characteristics of WIMPs appear to match those of a particle predicted by supersymmetry, the neutralino. While CDMS II watches for WIMPs, accelerator experiments seek to create neutralinos in particle collisions and measure their properties.