The Xenon 100 experiment is a brand new dark matter experiment, with as you might expect a 100 kilograms of Xenon fluid, at the bottom of an old mine, Gran Sasso laboratory in Italy. This is so much bigger than previous experiments that just 11 days of data, are supposed enough to rule out previous positive signals at CDMS, DAMA and CoGeNT. Contraversally this was supposed to be true, even at the lower end of the mass range for dark matter particles, which traditionally detectors with heavy elements (like Xenon) are not so sensitive to. Because Xenon experiment is so new some have worried that it isn't well calibrated yet, so Xenons first result has been high controversial. More on the Xenon experiment from around the web.