David O. Caldwell

Dark matter search results from the CDMS II experiment.

News from the Dark Side? Dark matter is thought to represent 85% of all matter in the universe and to have been responsible for the formation of structure in the early universe, but its nature is still a mystery. Ahmed et al. (p. 1619, published online 11 February; see the Perspective by Lang) describe the results from the completed Cryogenic Dark Matter Search (CDMS II) experiment, which searched for dark matter in the form of weakly interacting massive particles (WIMP). Two candidate signals were observed, whereas only one background event was expected. The probability of having two or more events from the background would have been 23%. The results of this analysis cannot be interpreted with confidence as evidence for WIMP interactions, but, at the same time, neither event can be ruled out as representing signal. Details of possible, but unlikely, detection events produced by dark matter are reported. Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 ± 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models.Z. Ahmed, D.S. Akerib, S. Arrenberg, C.N. Bailey, D. Balakishiyeva, L. Baudis, D.A. Bauer, P.L. Brink, T. Bruch, R. Bunker, B. Cabrera, D.O. Caldwell, J. Cooley, P. Cushman, M. Daal, F. DeJongh, M.R. Dragowsky, L. Duong, S. Fallows, E. Figueroa-Feliciano, J. Filippini, M. Fritts, S.R. Golwala, D.R. Grant, J. Hall, R. Hennings-Yeomans, S.A. Hertel, D. Holmgren, L. Hsu, M.E. Huber, O. Kamaev, M. Kiveni, M. Kos, S.W. Leman, R. Mahapatra, V. Mandic, K.A. McCarthy, N. Mirabolfathi, D. Moore, H. Nelson, R.W. Ogburn, A. Phipps, M. Pyle, X. Qiu, E. Ramberg, W. Rau, A. Reisetter, 7 T. Saab, B. Sadoulet, 13 J. Sander, R.W. Schnee, D.N. Seitz, B. Serfass, K.M. Sundqvist, M. Tarka, P. Wikus, S. Yellin, 14 J. Yoo, B.A. Young, and J. Zhang (CDMS Collaboration) Division of Physics, Mathematics & Astronomy, California Institute of Technology, Pasadena, CA 91125, USA Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA Fermi National Accelerator Laboratory, Batavia, IL 60510, USA Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Department of Physics, Queen’s University, Kingston, ON, Canada, K7L 3N6 Department of Physics, St. Olaf College, Northfield, MN 55057 USA Department of Physics, Santa Clara University, Santa Clara, CA 95053, USA Department of Physics, Southern Methodist University, Dallas, TX 75275, USA Department of Physics, Stanford University, Stanford, CA 94305, USA Department of Physics, Syracuse University, Syracuse, NY 13244, USA Department of Physics, Texas A & M University, College Station, TX 77843, USA Department of Physics, University of California, Berkeley, CA 94720, USA Department of Physics, University of California, Santa Barbara, CA 93106, USA Departments of Phys. & Elec. Engr., University of Colorado Denver, Denver, CO 80217, USA Department of Physics, University of Florida, Gainesville, FL 32611, USA School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455, USA Physics Institute, University of Zürich, Winterthurerstr. 190, CH-8057, Switzerland Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA

Evidence for anti-muon-neutrino ---> anti-electron-neutrino oscillations from the LSND experiment at LAMPF

A search for

Evidence for nu(mu) ---> nu(e) neutrino oscillations from LSND

\bar\nu_{\mu}\to \bar\nu_{e}

Results from a Low-Energy Analysis of the CDMS II Germanium Data

oscillations has been conducted at the Los Alamos Meson Physics Facility by using

Evidence for nu_mu -> nu_e Neutrino Oscillations from LSND

\bar\nu_\mu

Evidence for

from

\bar\nu_\mu\to\bar\nu_e

\mu^+

Oscillations from the LSND Experiment at LAMPF

decay at rest. The

Limits on Spin-Independent Interactions of Weakly Interacting Massive Particles with Nucleons from the Two-Tower Run of the Cryogenic Dark Matter Search

\bar\nu_e

Exclusion limits on the WIMP-nucleon cross section from the cryogenic dark matter search.

are detected via the reaction