1,785 research outputs found
When Dark Matter interacts with Cosmic Rays or Interstellar Matter: A Morphological Study
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
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review of assisted living laws of California and 11 other states, California's assisted living policy is significantly out of date.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
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 .Comment: 19 pages, matches JHEP published version. References added, minor
change
Putting Things Back Where They Belong: Tracing Cosmic-Ray Injection with H2
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
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
- …