Exclusion limits on the WIMP-nucleon cross-section from the Cryogenic Dark Matter Search

The Cryogenic Dark Matter Search (CDMS) employs low-temperature Ge and Si detectors to search for Weakly Interacting Massive Particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. For recoil energies above 10 keV, events due to background photons are rejected with >99.9% efficiency, and surface events are rejected with >95% efficiency. The estimate of the background due to neutrons is based primarily on the observation of multiple-scatter events that should all be neutrons. Data selection is determined primarily by examining calibration data and vetoed events. Resulting efficiencies should be accurate to about 10%. Results of CDMS data from 1998 and 1999 with a relaxed fiducial-volume cut (resulting in 15.8 kg-days exposure on Ge) are consistent with an earlier analysis with a more restrictive fiducial-volume cut. Twenty-three WIMP candidate events are observed, but these events are consistent with a background from neutrons in all ways tested. Resulting limits on the spin-independent WIMP-nucleon elastic-scattering cross-section exclude unexplored parameter space for WIMPs with masses between 10-70 GeV c^{-2}. These limits border, but do not exclude, parameter space allowed by supersymmetry models and accelerator constraints. Results are compatible with some regions reported as allowed at 3-sigma by the annual-modulation measurement of the DAMA collaboration. However, under the assumptions of standard WIMP interactions and a standard halo, the results are incompatible with the DAMA most likely value at >99.9% CL, and are incompatible with the model-independent annual-modulation signal of DAMA at 99.99% CL in the asymptotic limit.Comment: 40 pages, 49 figures (4 in color), submitted to Phys. Rev. D; v.2:clarified conclusions, added content and references based on referee's and readers' comments; v.3: clarified introductory sections, added figure based on referee's comment

Study of capital requirements for solar energy. Final report, Volume 1. Analysis of the macroeconomic effects of increased solar energy market penetration

This report defines the analytical framework for, and presents the results of, a study to determine the macroeconomic effects of increased market penetration of solar energy technologies over the 1977-2000 time period. For the purposes of this document, solar technologies are defined as wind, photovoltaics, ocean thermal electric (OTEC), small-scale (non-utility) hydroelectric and all solar active and passive thermal technologies. This research has been undertaken in support of the National Plan to Accelerate Commercialization (NPAC) of Solar Energy. The capital and operating requirements for three market penetration levels are first determined; the effects of these requirements on economic performance are then estimated using the Hudson-Jorgenson Energy/Economic Model. The analytical design, computational methods, data sources, assumptions and scenario configurations for this analysis are defined in detail. The results of the analysis of the economic impact of solar energy are presented in detail, and the implications of these results are discussed. Appendix A explains the methodology for transforming investment to capital stocks. Appendix B, which is provided in a separate volume, describes the Hudson-Jorgenson Model in greater detail. (WHK