Published in Physics World, 11 Feb 2010
Direct observations of dark matter – the substance thought to account for 80% of matter in the universe – are sketchy, at best. Some experiments have found what seem like dark-matter signals, while others looking within the same parameter range have found nothing. Yet there is a hypothetical candidate for dark matter, known as “inelastic” dark matter, that could reconcile such results – and now two teams of physicists have proposed new ways to see if it exists.
The story of inelastic dark matter begins over a kilometre beneath Gran Sasso mountain in Italy, which is home to the underground DAMA experiment. Here, a bank of detectors watches out for the flash of light that is expected when a dark-matter particle strikes a nucleus within the experiment. Although such collisions are very rare, in theory there should be more flashes in summer, when the Earth is orbiting against the prevailing “wind” of dark matter in our galaxy. […]
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