1,760 research outputs found

    Introduction to dark matter experiments

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    This is a set of four lectures presented at the Theoretical Advanced Study Institute (TASI-09) in June 2009. I provide an introduction to experiments designed to detect WIMP dark matter directly, focusing on building intuitive understanding of the characteristics of potential WIMP signals and the experimental techniques. After deriving the characteristics of potential signals in direct-detection experiments for standard WIMP models, I summarize the general experimental methods shared by most direct-detection experiments and review the advantages, challenges, and status of such searches (as of late 2009). Experiments are already probing SUSY models, with best limits on the spin-independent coupling below 10^-7 pb.Comment: 64 pages, 25 figures, based on lectures at 2009 Theoretical Advanced Study Institute in Elementary Particle Physics (TASI), Boulder, Colorado. This posted version benefits from some editing relative to the version in the published proceeding

    Status of direct searches for WIMP dark matter

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    Astrophysical observations indicate that about 23% of the energy density of the universe is in the form of non-baryonic particles beyond the standard model of particle physics. One exciting and well motivated candidate is the lightest supersymmetric partner particle (LSP), which could be a weakly interacting massive particle (WIMP) left over from the Big Bang. To determine that the LSP is the dark matter, it is necessary both to measure the particle's properties at an accelerator and to detect the particle in the galaxy directly (or indirectly). Direct detection of these particles requires sophisticated detectors to defeat much higher-rate backgrounds due to radioactivity and other sources. Promising techniques identify individual interactions in shielded fiducial volumes and distinguish nuclear-recoil signal events from electron-recoil backgrounds, based on the timing, energy density, and/or the division of the energy into signals of ionization, scintillation, or phonons. I review the techniques of the dozens of experiments searching for WIMPs and summarize the most interesting results and prospects for detection.Comment: 8 pages, 3 figures, to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200

    Avian chlamydiosis

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    The Dust Emissivity Spectral Index in the Starless Core TMC-1C

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    In this paper we present a dust emission map of the starless core TMC-1C taken at 2100 microns. Along with maps at 160, 450, 850 and 1200 microns, we study the dust emissivity spectral index from the (sub)millimeter spectral energy distribution, and find that it is close to the typically assumed value of beta = 2. We also map the dust temperature and column density in TMC-1C, and find that at the position of the dust peak (A_V ~ 50), the line-of-sight-averaged temperature is ~7 K. Employing simple Monte Carlo modeling, we show that the data are consistent with a constant value for the emissivity spectral index over the whole map of TMC-1C.Comment: 11 pages, including 5 pages of figures. Accepted to Ap

    Interest Deduction for Individuals: Review and Update

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    This article will review the current cases and rulings involving business, investment and qualified residence interest. It will point out areas of uncertainty as well as planning opportunities and pitfalls
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