Dark Matter Detected?
17 Apr 2008 – The DAMA/LIBRA experiment announced a confirmation of their previously found annual modulation signal in the count rate of a deep underground CsI detector. They see a modulation of +/-0.027 counts/kg/keV/day in the 2.5 to 3.5 keV band, but since the amplitude of modulation is supposed to be at most 7% of the dark matter signal this implies a dark matter generated event rate of 0.38 cts/kg/keV/day or more. The total rate in the experiment is 1.24 cts/kg/keV/day in this 2.5-3.5 keV band, so the dark matter rate is at least 31% of the total. With such a large fraction of the total rate coming from dark matter events in this 3 keV bump one would expect to see a corresponding bump in the total rate spectrum and it is actually present. But the CDMS experiment in the Soudan mine saw no counts in 397.8 kg-days of exposure, so the high DAMA/LIBRA rate seems unlikely – but not impossible given the differences in the detector materials and methods. However, it is peculiar that the a
