CDMS II: A Search for Cold Dark Matter with Cryogenic Detectors at the Soudan Mine

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Abstract AST 9978911 In the last decade considerable additional evidence has been gathered supporting the hypothesis that at least 90% of the mass in the universe is dark: it does not emit or absorb any form of electromagnetic radiation. Understanding this dark matter has become one of the more central problems in astronomy and cosmology. A number of observations indicate that the predominant form of the dark matter is nonbaryonic, presumably in the form of elementary particles produced in the early universe. Weakly Interactive Massive Particles form a particularly interesting generic class of candidates as there appears to be a convergence between cosmology and particle physics. The direct observation of the interaction of WIMPs in a terrestrial detector would be of tremendous importance to particle physics and cosmology. The observed WIMPs would be particles that reflect physics beyond the Standard Model of strong and electroweak interactions, and the identification of these WIMPs would solve the central problem of dark matter and help us understand the evolution of the early universe and the formation of structure. Because of a long development effort funded both by the National Science Foundation (through the Center for Particle Astrophysics) and the Department Of Energy, the sensor technology exists to provide a great step forward in this type of search, giving the best change for a positive result. The simultaneous measurement of the phonons and the ionization produced by the WIMP interactions provides a powerful discrimination against radioactive background, and this technique is now being utilized at Stanford, in the Cryogenic Dark Matter Search Experiment (CDMS I). This award, which is being supportred jointly by the Division of Astronomical Sciences, the Division of Physics, and the Office of Multidisciplinary Activities, will support construction and operation of a second generation experiment (CDMS II) at a deep site in the Soudan mine in northern Minnesota.