Dynamics of WIMPs in the solar system and implications for direct and indirect detection

Semi-analytic treatments of the evolution of orbits of weakly interacting massive particles (WIMPs) in the solar system suggest that the WIMPs bound to the solar system may enhance the direct detection rate relative to that of the unbound population by up to a factor of order unity, and boost the flux of neutrinos from WIMP annihilation in the Earth by up to two orders of magnitude. To test these important but uncertain results, we perform a suite of numerical orbit integrations to explore the properties of the bound WIMP population as a function of the WIMP mass and the scattering cross section with baryonic matter. For regions of WIMP parameter space presently allowed by experiments, we find that (i) the bound WIMP population enhances the direct detection rate by at most ~1% relative to the rate from unbound halo WIMPs; (ii) it is unlikely that planned km^3-scale neutrino telescopes will detect neutrinos from WIMP annihilation in the Earth; (iii) the event rate from neutrinos produced by WIMP annihilation in the Sun may be much smaller than implied by the usual calculations, which assume that WIMPs scattered onto bound orbits are rapidly thermalized in the Sun.Comment: 4 pages, 1 figure, to appear in the IDM2008 conference proceeding

Dark-matter decays and Milky Way satellite galaxies

We consider constraints on a phenomenological dark-matter model consisting of two nearly degenerate particle species using observed properties of the Milky Way satellite galaxy population. The two parameters of this model, assuming the particle masses are >~ GeV, are v_k, the recoil speed of the daughter particle, and tau, the lifetime of the parent particle. The satellite constraint that spans the widest range of v_k is the number of satellites that have a mass within 300 pc M300 > 5 x 10^6 solar masses, although constraints based on M300 in the classical dwarfs and the overall velocity function are competitive for v_k >~ 50 km/s. In general, we find that tau <~ 30 Gyr is ruled out for 20 km/s <~ v_k <~ 200 km/s, although we find that the limits on tau for fixed v_k can change constraints by a factor of ~3 depending on the star-formation histories of the satellites. We advocate using the distribution of M300 in Milky Way satellites determined by next-generation all-sky surveys and follow-up spectroscopy as a probe of dark-matter properties.Comment: 17 pages, 9 figures, submitted to Phys. Rev.

Data Center Interconnects at 400G and Beyond

Current trends in Data Center Interconnectivity are considered in the light of increasing traffic and under the constraint of limited cost and power consumption.Comment: This project has received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 762055 (BlueSpace project) and from the German ministry of education and research (BMBF) under contract 16KIS0477K (SENDATE Secure-DCI project

Getting the astrophysics and particle physics of dark matter out of next-generation direct detection experiments

The next decade will bring massive new data sets from experiments of the direct detection of weakly interacting massive particle (WIMP) dark matter. The primary goal of these experiments is to identify and characterize the dark-matter particle species. However, mapping the data sets to the particle-physics properties of dark matter is complicated not only by the considerable uncertainties in the dark-matter model, but by its poorly constrained local distribution function (the "astrophysics" of dark matter). In this Letter, I propose a shift in how to do direct-detection data analysis. I show that by treating the astrophysical and particle physics uncertainties of dark matter on equal footing, and by incorporating a combination of data sets into the analysis, one may recover both the particle physics and astrophysics of dark matter. Not only does such an approach yield more accurate estimates of dark-matter properties, but may illuminate how dark matter coevolves with galaxies.Comment: 4 pages, 4 figures, replaced to match version accepted by Phys. Rev.