2,312 research outputs found

    The prospectus and offering circular as sources of investment information

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    The purpose of this study is to determine the adequacy and reliability of information contained in the prospectus or offering circular issued in connection with new issues of common stocks. The study will be limited to issues of corporations that are just going public. That is, the first public offering of securities by corporations that have previously been privately owned. The study will be made from the viewpoint of the purchaser or prospective purchaser of such securities. Since most of the firms concerned in such issues are relatively new and untried, most purchasers are seeking price appreciation rather than income. To that extent, we are concerned with investment information only if investment is considered with in the broad sense of being any purchase of securities for profit. Certainly few of these issues could qualify as \u27investment securities under more stringent definitions of investment. For example, Graham and Dodd define an investment operation as, ... one which, upon thorough analysis, promises safety of principal and satisfactory return. 1 In purchasing first public offerings one must usually forego maximum safety in search of maximum profits. If this narrow definition of investment is accepted, this study will be concerned primarily with the use of the prospectus or offering circular as a source of speculative information, with speculation being defined here as the purchase of securities in the hope of profiting through price appreciation

    After LUX: The LZ Program

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    The LZ program consists of two stages of direct dark matter searches using liquid Xe detectors. The first stage will be a 1.5-3 tonne detector, while the last stage will be a 20 tonne detector. Both devices will benefit tremendously from research and development performed for the LUX experiment, a 350 kg liquid Xe dark matter detector currently operating at the Sanford Underground Laboratory. In particular, the technology used for cryogenics and electrical feedthroughs, circulation and purification, low-background materials and shielding techniques, electronics, calibrations, and automated control and recovery systems are all directly scalable from LUX to the LZ detectors. Extensive searches for potential background sources have been performed, with an emphasis on previously undiscovered background sources that may have a significant impact on tonne-scale detectors. The LZ detectors will probe spin-independent interaction cross sections as low as 5E-49 cm2 for 100 GeV WIMPs, which represents the ultimate limit for dark matter detection with liquid xenon technology.Comment: Conference proceedings from APS DPF 2011. 9 pages, 6 figure

    Sigma Terms of Light-Quark Hadrons

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    A calculation of the current-quark mass dependence of hadron masses can help in using observational data to place constraints on the variation of nature's fundamental parameters. A hadron's sigma-term is a measure of this dependence. The connection between a hadron's sigma-term and the Feynman-Hellmann theorem is illustrated with an explicit calculation for the pion using a rainbow-ladder truncation of the Dyson-Schwinger equations: in the vicinity of the chiral limit sigma_pi = m_pi/2. This truncation also provides a decent estimate of sigma_rho because the two dominant self-energy corrections to the rho-meson's mass largely cancel in their contribution to sigma_rho. The truncation is less accurate for the omega, however, because there is little to compete with an omega->rho+pi self-energy contribution that magnifies the value of sigma_omega by ~25%. A Poincare' covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is solved to obtain the current-quark mass dependence of the masses of the nucleon and Delta, and thereby sigma_N and sigma_Delta. This "quark-core" piece is augmented by the "pion cloud" contribution, which is positive. The analysis yields sigma_N~60MeV and sigma_Delta~50MeV.Comment: 22 pages, reference list expande

    Radiogenic and Muon-Induced Backgrounds in the LUX Dark Matter Detector

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    The Large Underground Xenon (LUX) dark matter experiment aims to detect rare low-energy interactions from Weakly Interacting Massive Particles (WIMPs). The radiogenic backgrounds in the LUX detector have been measured and compared with Monte Carlo simulation. Measurements of LUX high-energy data have provided direct constraints on all background sources contributing to the background model. The expected background rate from the background model for the 85.3 day WIMP search run is (2.6±0.2stat±0.4sys)×103(2.6\pm0.2_{\textrm{stat}}\pm0.4_{\textrm{sys}})\times10^{-3}~events~keVee1_{ee}^{-1}~kg1^{-1}~day1^{-1} in a 118~kg fiducial volume. The observed background rate is (3.6±0.4stat)×103(3.6\pm0.4_{\textrm{stat}})\times10^{-3}~events~keVee1_{ee}^{-1}~kg1^{-1}~day1^{-1}, consistent with model projections. The expectation for the radiogenic background in a subsequent one-year run is presented.Comment: 18 pages, 12 figures / 17 images, submitted to Astropart. Phy
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