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Dark Matter

Dark Matter. Evidence for Dark Matter Dark Matter Candidates How to search for DM particles? Recent puzzling observations (PAMELA, ATIC, EGRET). Dark Matter. coma.

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Dark Matter

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  1. Dark Matter • Evidence for Dark Matter • Dark Matter Candidates • How to search for DM particles? • Recent puzzling observations (PAMELA, ATIC, EGRET) "From neutrinos ....". DK&ER, lecture13

  2. Dark Matter coma • 1933 r. - Fritz Zwicky, COMA cluster. Rotation velocity of gallaxies around common center of mass too large for them to be in a bound system. • In 1970-80 – rotation velocity of gallaxies; halo of invisible matter (?) spherical halo of Dark Matter surrounding a gallaxy Invisible matter, only gravitational interactions "From neutrinos ....". DK&ER, lecture13 P. Mijakowski

  3. Dark Matter – Bullet Cluster • 2006 r. analysis of mass distribution in the region of passing through gallaxy clusters (1E0657-558) (*) • Gravitational lensing – gravitational potential (images from Hubble Space Telescope, European Southern Observatory VLT, Magellan)/ violet • X-rays - Chandra X-ray Observatory (NASA)/rose 1E0657-558 • Mass of gas typically 2x larger than the mass of visible matter in gallaxies • Result: concentration of gravitational mass is where gallaxies are • Region of X emission:only 10% of the total mass of the system • Comparison of both observations makes Dark Matter necessary "From neutrinos ....". DK&ER, lecture13 (*) D.Clowe et al. 2006 Ap. J. 648 L109 P. Mijakowski

  4. Gravitational lensing Einstein's Bullseyes "From neutrinos ....". DK&ER, lecture13 Elliptical galaxies have DM halos as spiral galaxies

  5. What do we know about ? Visible matter (stars, gas): Baryons visible or invisible calculated from BB nucleosynthesis Total matter deduced from gravitational potential energy of galaxies etc. Dark matter: Dark energy: „geometria płaska” k=0 "From neutrinos ....". DK&ER, lecture13

  6. < 7% of mass of gallactic halo (exp. EROS) structure formation requires CDM Dark Matter - candidates • Known particles • MACHO’s (Massive Astronomical Compact Halo Objects), np. brown dwarfs, neutron stars, black holes • Neutrinos (Hot Dark Matter - HDM) • Postulated particles: • Axions • WIMP-s (Weakly Interacting Massive Particles) - slow, massive, neutral particles, weakly interacting with matter(Cold Dark Matter - CDM) "From neutrinos ....". DK&ER, lecture13 P. Mijakowski

  7. WIMPs (WIMP – Weakly Interacting Massive Particle) We are looking for particles: • Neutral • With long lifetime ( τ ~ Universe lifetime) • Massive ( Mχ ~ 100 GeV) • Weakly interacting Examples of diagrams (neutralino) a good WIMP candidate: • neutralino χ (SUSY) – LSP (Lightest Supersymmetric Particle), is stable (conservation of R parity in SUSY) neutralino(χ) 18 GeV < Mχ < 7 TeV LEP cosmology "From neutrinos ....". DK&ER, lecture13 P. Mijakowski

  8. Trecoil~ keV detector Direct Detection • we measure energy of recoiling nuclei resulting from elastic scattering of WIMPs χ + (A,Z)at rest  χ + (A,Z)recoil Very many experiments are going on, and new projects studied Stay tuned. "From neutrinos ....". DK&ER, lecture13

  9. Direct detection – current experimental limits WARP(2.3 l. Ar) DAMA NaI, 90% CL region Zeplin II (Xe) • Region above lines is excluded with 3σ CL • DAMA 1.1x105 kg·d (7 years, 100 kg NaI) • Hidden assumptions: • interaction (spin dependance) • Galactic Halo Model Edelweiss (Ge) CDMS II, 2004-05 (Ge) (34 kg·d) XENON (10kg)2007, 136 kg·d CDMS II, 2007prediction "From neutrinos ....". DK&ER, lecture13

  10. ρχ χ χ ν Earth Z νμ σscatt χ ν Γcapture Γannihilation μ Indirect detection - neutrinos Sun detektor In neutrino telescopes no excess of neutrinos from Sun, Earth center, Gallaxy center when compared to the expected background. "From neutrinos ....". DK&ER, lecture13 P. Mijakowski

  11. Super-Kamiokande data sample • 1679.6 live days of SK-I • 1892 upward through-going muons • muon length > 7m Eμ>1.6 GeV • effective area: 1200 m2 • angular resolution: 1 deg Simulation of the background of atmospheric neutrinos with: • Bartol fluxes (1996) (event time sampled from data sample) • „Nuance” for neutrino interactions • muon energy loss in rock – Lipari, Stanev • detector simulation • oscillations S. Desai PhD thesis S.Desai et al., PRD D70, 83523 (2004) "From neutrinos ....". DK&ER, lecture13

  12. Upward-muons (from ν interactions) -SK Angles with respect to direction from: atm. bkg without oscil Earthcenter Sun Galactic center with oscil. with oscil. • No excess of neutrinos from the studied objects • Upper limits on muon fluxes are calculated Normalization: total # of MC events = # of data events "From neutrinos ....". DK&ER, lecture13

  13. Upward muons flux limits from various experiments From Galactic center SK SK From Earth’ s center From Sun SK "From neutrinos ....". DK&ER, lecture13

  14. Muon flux limits as functions of WIMP masses Wimps of larger mass produce tighter ν beams. Cones are calculated containing 90% of muons from WIMPs: Sun Earth’s center Galactic center "From neutrinos ....". DK&ER, lecture13 S.Desai et al., Phys.Rev. D70 (2004) 083523

  15. SuperK limit for neutralino elastic cross section (spin independent interactions) comparison with direct detection • Comparison with direct detection: model dependent, assuming only spin-independent interactions in Earth and Sun • Direct and Indirect event rates: Evt. rate in 1 kg Ge detector = Evt. Rate in 104-106 m2 of upward muon detector (assuming SI couplings) • Currently: lowest limit in direct detection -> XENON, ~10-7 pb (10-43 cm2) for a 100 GeV WIMP "From neutrinos ....". DK&ER, lecture13

  16. SuperK limit for neutralino elastic cross section (spin dependent) • Limit 100 times lower than from direct search experiments • DAMA annual modulation due to axial vector couplings ruled out by this result (Kamionkowski et al.) Kamionkowski, Ullio, Vogel JHEP 0107 (2001) 044 "From neutrinos ....". DK&ER, lecture13

  17. Some recent observations which can indicate Dark Matter particles in Universe "From neutrinos ....". DK&ER, lecture13

  18. Cosmic-ray Antimatter from Dark Matter annihilation Halo • Antimatter particles • can result from: • secondary interactions of primary cosmic rays • annihilation of WIMPs gravitationally confined in the galactic halo You are here Milky Way A plausible WIMP candidate is a neutralino χ, the lightest SUSY particle Most likely processes: "From neutrinos ....". DK&ER, lecture13

  19. PAMELA PAMELA a Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics • PAMELA is mounted on satellite Resurs-DK1, inside a pressurized container • launched June 2006 • minimum lifetime 3 years • data transmitted via Very high-speed Radio Link (VRL) scientific objectives: • Search for dark matter annihilation (e+ and p-bar spectra) • Search for anti-He (primordial antimatter) • Study composition and spectra of cosmic rays (including light nuclei) • Study solar physics and solar modulation • Study terrestrial magnetosphere and radiation belts "From neutrinos ....". DK&ER, lecture13

  20. PAMELA detector principle "From neutrinos ....". DK&ER, lecture13 M. Pearce 2009

  21. PAMELA results (positrons) best statistics so far: 151672 electrons 9430 positrons ...in 500 days in 1.5-100 GeV compared to other experiments • low energy -solar modulation effects • difference comparing to CAPRICE, HEAT, AMS -> previous solar cycle • 5-10 GeVcompatibility with other meas. • above 10 GeV • observed increase (*) O.Adriani et al. [PAMELA Collaboration], arXiv.0810.4994 (Oct 2008) "From neutrinos ....". DK&ER, lecture13

  22. PAMELA results (positrons) compared to secondary production (*) O.Adriani et al. [PAMELA Collaboration], arXiv.0810.4995 (Oct 2008) spectrum shape completely different ???? secondary production (Moskalenko&Strong) "From neutrinos ....". DK&ER, lecture13

  23. Baloon born experiment for C.R measurement Operated from McMurdo, Antarctica ATIC-1 15 days (2000/2001) ATIC-2 17 days (2002/2003) flights @ 36km ATIC Advanced Thin Ionization Calorimeter "From neutrinos ....". DK&ER, lecture13

  24. "From neutrinos ....". DK&ER, lecture13

  25. ATIC results (*) J. Chang, et al. [ATIC Collaboration], Nature, 456, 362 (2008) e+e- flux ATIC (red points);AMS (green stars); HEAT (open black triangles); BETS (open blue circles), PPB-BETS (blue crosses); emulsion chambers (black open diamonds); solid curve – galactic spectrum (GALPROP); dashed curve - solar modulated electron spectrum; "From neutrinos ....". DK&ER, lecture13

  26. Neutralino annihilation fit to PAMELA & ATIC data D.Hooper. A.Stebbins ,K.Zurek, arxiv.0812.3202 (Dec 2008) • To normalize ATIC & PAMELA data a very large or dense clump of DM is required • -> annihilation rates (per second): secondary production (Moskalenko&Strong) ASSUMPTIONS • WIMPs annihilation only to W+W- • Annihilation in nearby clump (could be a point source like) "From neutrinos ....". DK&ER, lecture13

  27. DM annihilation to gammas - EGRET 50-100 GeV neutralino annihilation? • EGRET excess in diffuse galactic gamma ray flux "From neutrinos ....". DK&ER, lecture13

  28. Summary • Dark Matter consistently needed to understand various astrophysical observations • According to current studies it constitutes around 24% of the total energy of the Universe • The searches of Dark Matter candidates are going on in various experiments: • direct searches • indirect searches using neutrinos from WIMP annihilation • Recently some puzzling observations (PAMELA, ATIC, EGRET) - could be due to DM?? "From neutrinos ....". DK&ER, lecture13

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