An experiment buried deep beneath the forests of Minnesota has seen two events that could be the first direct detection of dark matter. The finding is tentative - it's still possible that conventional particles might be causing the signal - but, if confirmed, it will mark the end of a decades-long search for the mysterious particles. Read more
Title: A Search for WIMPs with the First Five-Tower Data from CDMS Authors: CDMS Collaboration
We report first results from the Cryogenic Dark Matter Search (CDMS II) experiment running with its full complement of 30 cryogenic particle detectors at the Soudan Underground Laboratory. This report is based on the analysis of data acquired between October 2006 and July 2007 from 15 Ge detectors (3.75 kg), giving an effective exposure of 121.3 kg-d (averaged over recoil energies 10 - 100 keV, weighted for a weakly interacting massive particle (WIMP) mass of 60GeV/c²). A blind analysis, incorporating improved techniques for event reconstruction and data quality monitoring, resulted in zero observed events. This analysis sets an upper limit on the WIMP-nucleon spin-independent cross section of 6.6 x 10^-44 cm² (4.6 x 10^-44 cm² when combined with previous CDMS Soudan data) at the 90% confidence level for a WIMP mass of 60 GeV/c². By providing the best sensitivity for dark matter WIMPs with masses above 42 GeV/c², this work significantly restricts the parameter space for some of the favoured supersymmetric models.