1,785 research outputs found

    When Dark Matter interacts with Cosmic Rays or Interstellar Matter: A Morphological Study

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    Excess emission over expected diffuse astrophysical backgrounds in the direction of the Galactic center region has been claimed at various wavelengths, from radio to gamma rays. Among particle models advocated to explain such observations, several invoke interactions between dark matter particles and ordinary matter, such as cosmic rays, interstellar gas or free electrons. Depending on the specific interstellar matter particles' species and energy, such models predict distinct morphological features. In this study we make detailed predictions for the morphology of models where the relevant electromagnetic emission is proportional to the product of the dark matter density profile and the density of interstellar matter or cosmic rays. We compare the predicted latitudinal and longitudinal distributions with observations, and provide the associated set of relevant spatial templates.Comment: 10 pages, 4 figures, submitted; Supplementary code and emission skymaps available at http://planck.ucsc.edu/dmcr-morpholog

    Best Practices in Assisted Living: Considering Potential Reforms for California

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    Based on a review of assisted living laws of California and 11 other states, California's assisted living policy is significantly out of date. An assisted living resident today is likely to have significant care needs, but California's law in general has low standards for quality of care. Unlike many other states, California has not adjusted adequately to the sharp increase in residents' care needs over the past 10 to 15 years. California's assisted living law was enacted in 1985, and has been amended only intermittently since then. It requires significant revision in order to keep pace with the new realities of assisted living

    Gravitino Dark Matter and Flavor Symmetries

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    In supersymmetric theories without R-parity, the gravitino can play the role of a decaying Dark Matter candidate without the problem of late NLSP decays affecting Big Bang Nucleosynthesis. In this work, we elaborate on recently discussed limits on R-parity violating couplings from decays to antideuterons and discuss the implications for two classes of flavor symmetries: horizontal symmetries, and Minimal Flavor Violation. In most of the parameter space the antideuteron constraints on R-parity violating couplings are stronger than low-energy baryon-number-violating processes. Even in the absence of flavor symmetries, we find strong new limits on couplings involving third-generation fields, and discuss the implications for LHC phenomenology. For TeV scale superpartners, we find that the allowed MFV parameter space is a corner with gravitino masses smaller than O(10) GeV and small tanβ\tan\beta.Comment: 19 pages, matches JHEP published version. References added, minor change

    Putting Things Back Where They Belong: Tracing Cosmic-Ray Injection with H2

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    At present, all physical models of diffuse Galactic gamma-ray emission assume that the distribution of cosmic-ray sources traces the observed populations of either OB stars, pulsars, or supernova remnants. However, since H2-rich regions host significant star formation and numerous supernova remnants, the morphology of observed H2 gas should also provide a physically motivated, high-resolution tracer for cosmic-ray injection. We assess the impact of utilizing H2 as a tracer for cosmic-ray injection on models of diffuse Galactic gamma-ray emission. We employ state-of-the-art 3D particle diffusion and gas density models, along with a physical model for the star-formation rate based on global Schmidt laws. Allowing a fraction, f_H2, of cosmic-ray sources to trace the observed H2 density, we find that a theoretically well-motivated value f_H2 ~ 0.20 -- 0.25 (i) provides a significantly better global fit to the diffuse Galactic gamma-ray sky and (ii) highly suppresses the intensity of the residual gamma-ray emission from the Galactic center region. Specifically, in models utilizing our best global fit values of f_H2 ~ 0.20 -- 0.25, the spectrum of the galactic center gamma-ray excess is drastically affected, and the morphology of the excess becomes inconsistent with predictions for dark matter annihilation.Comment: 5 pages, 3 figures, submitted to PR

    High throughput microbalance and methods of using same

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    A method and apparatus for measurement of mass of small sample sizes. The method and apparatus is particularly adapted for providing microbalance measurement of solid materials as part of a combinatorial research program. The method and apparatus contemplate monitoring the response of a resonator holding a sample and correlating the response with mass change in the samples
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