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Searches for Dark Matter

A. Bashir, U. Cotti, C. de Leon, A. Raya, V. Villanueva and L. Villaseñor IFM-UMSNH XI Workshop on Particles & Fields DPyC-SMF Tuxtla Gutierrez, Chiapas 8-13 November, 2007. Searches for Dark Matter. Outline. Evidences for Dark Matter DM Candidates Direct & indirect detection

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Searches for Dark Matter

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  1. A. Bashir, U. Cotti, C. de Leon, A. Raya, V. Villanueva and L. Villaseñor IFM-UMSNH XI Workshop on Particles & Fields DPyC-SMF Tuxtla Gutierrez, Chiapas 8-13 November, 2007 Searches for Dark Matter

  2. Outline Evidences for Dark Matter DM Candidates Direct & indirect detection Running & future experiments Conclusion

  3. A Mexican group submitted a proposal to study DM in an underground lab to Conacyt in 2007 R&D money will possibly be granted in 2008

  4. Evidence for Dark Matter Fritz Zwicky (1933) measured the velocities of the individual galaxies. He concluded that “dark” matter is required to hold the cluster Coma cluster, 350 M ly

  5. Evidence for Dark Matter • Flat Rotation curves of Galaxies. V. Rubin and W.K. Ford (1970) “What you see is not what you get.” • vc ~ r 1/2 Alternative Explanations • Modified Newtonian Dynamics (Moglim 1983) • Modified Gravity such as Scalar tensor vector gravity theory (Moffat 2006) • Local density : 0.3 GeV/cm3

  6. Measured over and over Each plot contains 50-100 galaxies according to luminosity M. Persic et al. 1996

  7. BB Nucleogenesis: Determines the present baryon mass density to only ~ 4% of critical density Widths of curves indicate 95% CL for the abundance predictions Measurements are shown as boxes. Non baryon dark mass is required! D. Tytler, J. M. O’Meara, N. Suzuki, and D. Lubin, astro-ph/0001318

  8. Evidence for Dark Matter Bullet Cluster (Clowe et al., 2006) two colliding Clusters of Galaxies at a distance of about 3.4 billion light years White – Visible Red – X Rays Blue - Grav. Lensing evidence against Modified Newtonian Dynamics (MOND) NASA RELEASE 06-297: "These observations provide the strongest evidence yet that most of the matter in the universe is dark"

  9. White – Visible

  10. Blue - Grav. Lensing

  11. Red – X Rays

  12. White – Visible Red – X Rays Blue - Grav. Lensing

  13. Evidence for Dark Matter Lambda-Cold Dark Matter (concordance) model explains cosmic microwave background observations (WMAP), as well as large scale structure observations (Sloan Digital Sky Survey) and supernovae Ia data of the accelerating expansion of the universe. The Composition of the Universe

  14. ΛCDM MODEL (Spergel et al. 2006)

  15. Particle Candidate for Cold Dark Matter: WIMP Weakly Interacting Massive Particle Stable, TeV scale, electrically neutral, only weakly interacting No such candidate in the Standard Model Good candidate: neutralino, Lightest Supersymmetric Particle (LSP) in SUSY with m ~ 10 GeV to 10 TeV Linear combination of the zino, the photino and the neutral higgsinos May be produced at the LHC

  16. Particle Candidate for Dark Matter But there are many other possibilities (techni-baryons, gravitino, axino, invisible axion, WIMPZILLAS( Godzilla-sized version of WIMPS, ruled out by Auger data), etc)

  17. WIMP Dark Matter Produced in early Universe They are in thermally equilibrium at high temperature Decouple when expansion rate ~ interaction rate Density left-over from annihilation depends on cross section Increasing <Av> Comoving number density Nequillibrium X=m/Temperature (time ) E.W. Kolb and M.S. Turner, The Early Universe

  18. WIMP DETECTION   f  f Scattering   • Direct Detection of halo particles in terrestrial detectors CDMS-II, ZEPLIN Edelweiss, DAMA, GENIUS, etc

  19. (direct) Detection method Since they are neutral and stable, what we can expect is only a collision with ordinary matter. Electron recoil does not give enough energy but nuclear recoil gives ~100keV if mDM~O(100GeV). Energy deposit Dark Matter particles

  20. WIMP DETECTION  f   f Annihilation _  p   e+  • Indirect Detection • SuperK, AMANDA, ICECUBE, GLAST • Search for neutrinos, gamma rays, radio waves, antiprotons, positrons in earth- or space-based experiments Direct and indirect methods are complementary techniques along with a possible discovery at the LHC

  21. WIMP signatures (Direct Det) Nuclear recoils Neutrons (produce similar recoils with sigma 1020 higher, 108-9 background reduction needed Recoil spectrum shape Exponential (as most bkg) Shape for backgrounds : electron/nuclear recoils Absence of multiple scattering (against neutron) Uniform rate throughout volume (against surface radioactivity) Directionality of nuclear recoils Annual rate modulation

  22. WIMP signatures (Direct Det)

  23. Current direct detection experiments Discrimination Name Location Technique Material Status CUORICINO Gran Sasso Heat 41 kg TeO2 running GENIUS-TF Gran Sasso Ionization 10 to 40 kg Ge in N2 running ??? HDMS Gran Sasso Ionization 0.2 kg Ge diodes stopped IGEX Canfranc Ionization 2 kg Ge Diodes stopped DAMA Gran Sasso Light 100 kg NaI stopped LIBRA Gran Sasso Light 250 kg NaI running NaIAD Boulby mine Light 46 kg NaI stopped ZEPLIN-I Boulby mine Light 4 kg Liquid Xe stopped XENON Surface to GS Light+ Ionization 3 to 10 kg Liquid Xe running ZEPLIN II Boulby mine Light+ Ionization 6 kg Liquid Xe running CDMS-I Stanford Heat + Ionization 1 Kg Ge + 0.2 Kg Si stopped CDMS-II Soudan mine Heat + Ionization 2 to 7 kg Ge + 0.4 to 1.4 Kg Si running CRESST-I Gran Sasso Heat + Light 0.262 kg Al2O3 stopped CRESST-II Gran Sasso Heat + Light 0.6 to 9.9 kg CaWO4 running EDELWEISS-I Modane Heat + Ionization 1 kg Ge stopped EDELWEISS-II Modane Heat + Ionization 10 to 30 kg Ge In istallation PICASSO SNO Bubble chamber 20 g Freon running ROSEBUD Canfranc Heat + Light 50 g Al2O3 + 67 g Ge + 54 g CaWO4 running None Statistical Event-by-event

  24. B. Sadoulet KEKTC6

  25. 90% C.L. exclusion limits on WIMP-nucleon scattering cross-section (spin-independent) CDMS (2006)

  26. CDMS II Spin independent 90% Exclusion limits mSUGRA split-SUSY

  27. NaI NaI PMT PMT NaI NaI NaI scintillation : DAMA • Based in Gran Sasso lab (3500 mwe) • 100 kg of NaI(Tl) • Exposure : 107731 kg.d • Coincidence between 2 PMTs • Pulse shape rejection inefficient at 2 keVee

  28. NaI scintillation : DAMA • Used annual modulation • Claim annual modulation at 6.3σ over 7 annual cycles • Mχ ~ 52 GeV/c² • σn~ 7.2 10-6 pb • Not compatible with other experiments (CDMS, ZEPLIN, EDELWEISS) • Future = LIBRA (250 kg of NaI) DM density ~0.3GeV/cc 100GeV WIMPs  1 WIMP / 7cm cubic, =105/cm2/sec Single-hits events residual rates

  29. Muon-veto paddles encasing outer lead and polyethylene shielding Dilution Refrigerator Electronics stem from Icebox Cold stem to Icebox Icebox can take 7 towers with 6 ZIP detectors each CDMS II at Soudan Depth of 2000 mwe reduces neutron background from~1 / kg / day to ~1 / kg / year 500 Hz muons in 4 m2 shield Stanford UndergroundFacility Log10(Muon Flux) (m-2s-1) 1 per minute in 4 m2 shield Experimental apparatus Depth (mwe)

  30. Heat-ionization: CDMS-II FET cards SQUID cards 4 K 0.6 K 0.06 K 0.02 K ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) • 4x250g Ge + 2x100g Si • Net exposure: 19.4 kg.d • Detector = ZIP (sensitive to athermal phonon) • Active muon veto + shielding (PE + Pb)

  31. CDMS II Detector Deployment • Identical Icebox as CDMS I, but fits seven towers. • Each tower (T1-7) contains three Ge and three Si ZIP detectors interlaced. • Total mass of Ge = 7 x 3 x 0.25 kg > 5 kg • Total mass of Si = 7 x 3 x 0.10 kg > 2 kg (Extra polyethylene shield in SUF icebox only allows 3 towers to be run at SUF simultaneously.) T3 T4 T1 T2 T5 T7 T6

  32. Heat-ionization: CDMS-II Rejection of background surface events with timing cuts

  33. CDMS I (1995-1999) • Results for scalar-interacting (~A2) WIMPs probed are best upper limits of any experiment for the mass range 10 to 35 GeV. • CDMS data are incompatible with DAMA signal at high confidence. • Sensitivity limited by external neutron background from muons interacting in surrounding rock. • CDMS II (1999-2005) • Construction underway at deep site: Soudan, Minnesota. • First tower of 6 detectors ready for Soudan - they exceed performance expectations - “First Dark” January 2003. • Reduction of neutron background by factor of 2.3 due to installation of internal moderator in agreement with Monte Carlo predictions. • More work required on surface-beta rejection/identification/subtraction in order to fully utilize deep site?

  34. Neutrinos from the Earth (& Sun – but Sun more difficult for AMANDA  IceCUBE)

  35. IceCube AMANDA’s BIG BROTHER: 1 km3 of Ice 4200 PMTs on 70 Strings 1450-2450 m ~10 Angular Resolution to Mu Neutrinos IceTop Air Shower Array to Veto Downgoing Muons Digitized/Time-Stamped at Each PMT Started Deploying 2005; Construction Finished ~2011

  36. Gamma-ray Large Area Space Telescope GLAST Large Area Telescope (LAT) • GLAST will search for WIMP annihilation gamma rays from galactic center, galactic halo, galactic satellites and extragalactic • To be launched in late 2007, will survey the gamma-ray sky in the energy range of 20MeV-300 GeV. • GLAST will have a very broad science menu that includes: • Systems with supermassive black holes (Active Galactic Nuclei) • Gamma-ray bursts (GRBs) • Pulsars • Solar physics • Origin of Cosmic Rays • Probing the era of galaxy formation, optical-UV background light • Solving the mystery of the high-energy unidentified sources • Discovery! Particle Dark Matter? Other relics from the Big Bang? Extra dimensions? Testing Lorentz invariance. New source classes. Kathy Turner, 24May2006

  37. Conclusion • The existence of Nonbaryonic Dark Datter has been definitely established • CDM is favoured • Supersymmetric particles (in particular, neutralinos) are still among the best-motivated candidates • New direct and indirect detection experiments will reach deep into theory parameter space • The various indirect and direct detection methods are complementary to each other and to LHC • The hunt is going on – many new experiments coming! • The dark matter problem may be near its (s)solution…

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