New limits on spin-independent and spin-dependent couplings of low-mass WIMP dark matter with a germanium detector at a threshold of 220 eV

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Lin S. T. , Li H. B. , Li X., Lin S. K. , Wong H. T. , Deniz M., ...More

PHYSICAL REVIEW D, vol.79, no.6, 2009 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 79 Issue: 6
  • Publication Date: 2009
  • Doi Number: 10.1103/physrevd.79.061101
  • Journal Name: PHYSICAL REVIEW D
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Middle East Technical University Affiliated: No


An energy threshold of (220 +/- 10) eV was achieved at an efficiency of 50% with a four-channel ultralow-energy germanium detector, each with an active mass of 5 g. This provides a unique probe to weakly interacting massive particles (WIMP) dark matter with mass below 10 GeV. With a data acquisition live time of 0.338 kg-day at the Kuo-Sheng Laboratory, constraints on WIMPs in the galactic halo were derived. The limits improve over previous results on both spin-independent WIMP-nucleon and spin-dependent WIMP-neutron cross-sections for WIMP mass between 3 and 6 GeV. Sensitivities for full-scale experiments are projected. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments.