Exclusion limits on the WIMP-nucleon cross section from the first run of the Cryogenic Dark Matter Search in the Soudan Underground Laboratory

Journal Article · Thu Sep 01 04:00:00 EDT 2005 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.72.052009· OSTI ID:20711413

Akerib, D S; Bailey, C N; Dragowsky, M R; Driscoll, D D; Hennings-Yeomans, R; Kamat, S; Perera, T A; Schnee, R W; Wang, G ^[1]; Armel-Funkhouser, M S; Daal, M; Filippini, J; Lu, A; Mandic, V; Meunier, P; Mirabolfathi, N; Issac, M.C. Perillo; Rau, W; Seitz, D N; Serfass, B ^[2]

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1. Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106 (United States)
2. Department of Physics, University of California, Berkeley, California 94720 (United States); and others

The Cryogenic Dark Matter Search (CDMS-II) employs low-temperature Ge and Si detectors to seek weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei. Simultaneous measurements of both ionization and phonon energy provide discrimination against interactions of background particles. For recoil energies above 10 keV, events due to background photons are rejected with >99.99% efficiency. Electromagnetic events very near the detector surface can mimic nuclear recoils because of reduced charge collection, but these surface events are rejected with >96% efficiency by using additional information from the phonon pulse shape. Efficient use of active and passive shielding, combined with the 2090 m.w.e. overburden at the experimental site in the Soudan mine, makes the background from neutrons negligible for this first exposure. All cuts are determined in a blind manner from in situ calibrations with external radioactive sources without any prior knowledge of the event distribution in the signal region. Resulting efficiencies are known to {approx}10%. A single event with a recoil of 64 keV passes all of the cuts and is consistent with the expected misidentification rate of surface electron recoils. Under the assumptions for a standard dark matter halo, these data exclude previously unexplored parameter space for both spin-independent and spin-dependent WIMP-nucleon elastic scattering. The resulting limit on the spin-independent WIMP-nucleon elastic-scattering cross section has a minimum of 4x10{sup -43} cm{sup 2} at a WIMP mass of 60 GeVc{sup -2}. The minimum of the limit for the spin-dependent WIMP-neutron elastic-scattering cross section is 2x10{sup -37} cm{sup 2} at a WIMP mass of 50 GeVc{sup -2}.

• OSTI ID: 20711413
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 5 Vol. 72; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CALIBRATION
CHARGE COLLECTION
CROSS SECTIONS
DISTRIBUTION
EFFICIENCY
ELASTIC SCATTERING
ELECTRONS
GE SEMICONDUCTOR DETECTORS
IONIZATION
KEV RANGE
NEUTRONS
NONLUMINOUS MATTER
PARTICLE INTERACTIONS
PHONONS
PHOTONS
RECOILS
SI SEMICONDUCTOR DETECTORS
SPIN
UNDERGROUND