* Astronomy

Blobrana · L

RE: WIMP dark matter

Blobrana · L

Title: Exclusion of canonical WIMPs by the joint analysis of Milky Way dwarfs with Fermi
Authors: Alex Geringer-Sameth, Savvas M. Koushiappas (Brown University)
(Version v2)

Dwarf spheroidal galaxies are known to be excellent targets for the detection of annihilating dark matter. We present new limits on the annihilation cross section of Weakly Interacting Massive Particles (WIMPs) based on the joint analysis of seven Milky Way dwarfs using a frequentist Neyman construction and Pass 7 data from the Fermi Gamma-ray Space Telescope. We exclude generic WIMP candidates annihilating into b-bbar with mass less than 40 GeV that reproduce the observed relic abundance. To within 95% systematic errors on the dark matter distribution within the dwarfs, the mass lower limit can be as low as 19 GeV or as high as 240 GeV. For annihilation into tau+tau- these limits become 19 GeV, 13 GeV, and 80 GeV respectively.

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Blobrana · L

Title: Final results of the EDELWEISS-II WIMP search using a 4-kg array of cryogenic germanium detectors with interleaved electrodes
Authors: EDELWEISS Collaboration: E. Armengaud, C. Augier, A. Benoît, L. Bergé, J. Blümer, A. Broniatowski, V. Brudanin, B. Censier, M. Chapellier, F. Charlieux, P. Coulter, G. A. Cox, X. Defay, M. De Jesus, Y. Dolgorouki, J. Domange, L. Dumoulin, K. Eitel, D. Filosofov, J. Gascon, G. Gerbier, J. Gironnet, M. Gros, S. Henry, S. Hervé, A. Juillard, H. Kluck, V. Kozlov, H. Kraus, V. A. Kudryavtsev, P. Loaiza, S. Marnieros, X-F. Navick, C. Nones, E. Olivieri, P. Pari, L. Pattavina, B. Paul, M. Robinson, S. Rozov, V. Sanglard, B. Schmidt, S. Scorza, S. Semikh, A-S. Torrento-Coello, L. Vagneron, M-A. Verdier, R. J. Walker, E. Yakushev

The EDELWEISS-II collaboration has completed a direct search for WIMP dark matter with an array of ten 400-g cryogenic germanium detectors in operation at the Laboratoire Souterrain de Modane. The combined use of thermal phonon sensors and charge collection electrodes with an interleaved geometry enables the efficient rejection of gamma-induced radioactivity as well as near-surface interactions. A total effective exposure of 384 kg.d has been achieved, mostly coming from fourteen months of continuous operation. Five nuclear recoil candidates are observed above 20 keV, while the estimated background is less than 3.0 events. The result is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 4.4x10^-8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints are also set on models where the WIMP-nucleon scattering is inelastic.

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