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Gregory D. Mack, The Ohio State University Dept. of Physics

Gregory D. Mack, The Ohio State University Dept. of Physics. PASCOS 2006 September 13, 2006. Gregory D. Mack, The Ohio State University Dept. of Physics. PASCOS 2006 September 13, 2006. DM Annihilation Cross Section Limits.

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Gregory D. Mack, The Ohio State University Dept. of Physics

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  1. Gregory D. Mack, The Ohio State University Dept. of Physics PASCOS 2006 September 13, 2006

  2. Gregory D. Mack, The Ohio State University Dept. of Physics PASCOS 2006 September 13, 2006

  3. DM Annihilation Cross Section Limits • DM density profiles … cusps or cores? • Kaplinghat, Knox, and Turner (KKT)* proposed a large enough cross section to turn a cusp into a core. • Brings question of “How big can <σ v> be?” • Hui’s** unitaritybound is the only strict, model-independent upper limit * : Kaplinghat, Knox, and Turner, PRL 88, 3335 (2000); ** Hui PRL 86, 3467 (2001)

  4. What Products Should We Look For? • Disappearance of DM corresponds to appearance of products • Invisible vs. visible … nothing SM is invisible • KKT requires Br(photons) < 10-10 • Conservatively constrain total dark matter annihilation cross section by looking at neutrino appearance instead of photon appearance …. Br(neutrino) = 100%

  5. Diffuse Neutrino Flux • Galactic Center is problematic at best • Look at diffuse contribution from all galaxies • Annihilation signal depends on density squared … “clumpiness” matters Adapted from Ullio, Bergstrom, Edsjo, and Lacey PRD 66, 123502 (2002) and Bergstrom, Edsjo and Ullio PRL 87, 251301 (2001) • Δ2 for NFW: 2 x 105 ; Moore: 2 x 106 or higher… clumpiness relative to smooth DM

  6. Atmospheric Neutrino Background • Look for redshift-smeared bump on the atmospheric neutrino background, from monoenergetic neutrinos • Analyze in half-order of magnitude bins • Require finding 100% of signal in the bin Beacom, Bell, Mack astro-ph/0608090

  7. Atmospheric Neutrino Background • AMANDA and SK data support the prohibition of such a signal Ashie, et al (Super-K) PRD 71, 112005 (2005), Fully-contained events Munich (AMANDA), astro-ph/0509330

  8. New Model Independent Constraint • Rules out KKT, large annihilation cross sections • Covers large range of masses until Unitarity takes over Beacom, Bell, Mack astro-ph/0608090

  9. Conclusions • Created a new, model independent bound on the dark matter annihilation cross section, extending over an interesting mass range • Rules out cusps being able to be modified by annihilation; corresponds to creating a core within only the inner 1 pc of a Milky Way, NFW galaxy • Analysis can be improved greatly through various methods (being less conservative, stricter limits on data …)

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