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New Experimental Limits on the Existence of Strongly Interacting Dark Matter Particles

New Experimental Limits on the Existence of Strongly Interacting Dark Matter Particles. XXXVI th Recontres de Moriond Very High Energy Phenomena in the Universe 24 January 2001 Dan Javorsek, Ephraim Fischbach, Dave Elmore, and Tom Miller Purdue University, West Lafayette, IN 47907

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New Experimental Limits on the Existence of Strongly Interacting Dark Matter Particles

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  1. New Experimental Limits on the Existence of Strongly Interacting Dark Matter Particles XXXVIth Recontres de Moriond Very High Energy Phenomena in the Universe 24 January 2001 Dan Javorsek, Ephraim Fischbach, Dave Elmore, and Tom Miller Purdue University, West Lafayette, IN 47907 Doug Oliver and Vigdor Teplitz Southern Methodist University, Dallas, TX 75275

  2. Overview • What is a SIMP? • Motivations for SIMPs • The Dark Matter Problem • Ultra High Energy Cosmic Rays • Lightest Supersymmetric Particle • Our Experiment • First Results • Future Work Purdue University Department of Physics

  3. SIMPs X Au • Strongly Interacting Massive Particles • Neutral Particle • Mass > 1 GeV/c2Mproton 1 GeV • Bound by the strong force to a massive (high Z) stable atom (Au) • SIMPs may manifest as an anomalous isotope • Recent developments in particle physics and cosmology prompts searches for superheavy particles Purdue University Department of Physics

  4. Motivation: Dark Matter • Starkmann et al., Phys. Rev. D 41,3594 (1990) • Mohapatra & Teplitz, PRL 81, 3079 (1998) • If : sss ~ 1/Ms • Then : SIMPs can have sufficient abundance to saturate the cosmic density or galactic halo • SIMPs masses needed to saturate • Cosmic density MS> 103.5 GeV • Galactic halo MS< 100 GeV Purdue University Department of Physics

  5. Motivation: UHECR • Ultra High Energy Cosmic Rays (UHECRs) • Lose energyscattering with the cosmic background radiation (GZK) • To date, we have more than 700 confirmed events above the GZK cutoff (1019 eV) • Models of Albuquerque, Farrar, and Kolb suggest [Phys. Rev. D 59, 015021 (1998)] 10 GeV/c2 < MS < 50 GeV/c2 Purdue University Department of Physics

  6. Motivation: SUSY • Mohapatra & Nandi, PRL 79, 181 (1997) • Chacko et al., Phys. Rev. D56, 5466 (1997) • Raby, Phys. Rev. D 56, 2852 (1997) • suggest thegluinois the lightest supersymmetric particle (LSP) Purdue University Department of Physics

  7. The Experiment • Use Accelerator to search for anomalously heavy isotopes of Au Purdue University Department of Physics

  8. Results • Scanned SIMP mass rangefrom 2.8-144 GeV/c2 • Scanned both lab gold and Australian gold • Calculated the abundance of Au nuclei with SIMPs to those without Purdue University Department of Physics

  9. Results M’ = effective SIMP mass = MX-MAu = MS-|EB| Purdue University Department of Physics

  10. ResultsMohapatra et al., Phys. Rev. D 60, 115013 (1999) Purdue University Department of Physics

  11. Geological Samples • Western Australia • 15 cm of surface using a metal detector • Exposure age 50 million years • Northwestern Arizona • Mineral Park District (Gold Basin) • Exposure age  5 million years • Western North Carolina • Collected from streams in the Appalachians • South of glaciated area affected by the Ice Age • Deposits formed  570 million years ago Purdue University Department of Physics

  12. Exotic Samples • Long Duration Exposure Facility (LDEF) • Part of the Meteoroid and Exposure Module • Exposed to space from 1984 to 1990 • Performed 32,422 Earth orbits • Experienced ½ a solar cycle • Iron Meteorite • Beam dump from Brookhaven National Laboratory Purdue University Department of Physics

  13. Conclusions • SIMP abundance must be less than 1 x 10-11 • Future Work • Increase mass scan range (up to 1 TeV/c2) • Include more diverse samples • LDEF, Brookhaven, Meteorite, • Arizona, NC, Dentists & Jewlers • Search in Lead and Uranium Purdue University Department of Physics

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