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DARK2007 Sydney, Sept 24 th -28 th , 2007

The Prospects for the Search for Dark Matter with GLAST Brian L. Winer The Ohio State University LAT Dark Matter and New Physics Working Group. DARK2007 Sydney, Sept 24 th -28 th , 2007. GLAST LAT Collaboration. United States California State University at Sonoma

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DARK2007 Sydney, Sept 24 th -28 th , 2007

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  1. The Prospects for the Search for Dark Matter with GLAST Brian L. Winer The Ohio State University LAT Dark Matter and New Physics Working Group DARK2007 Sydney, Sept 24th-28th, 2007

  2. GLAST LAT Collaboration United States California State University at Sonoma University of California at Santa Cruz - Santa Cruz Institute of Particle Physics Goddard Space Flight Center – Laboratory for High Energy Astrophysics Naval Research Laboratory The Ohio State University Stanford University (SLAC and HEPL/Physics) University of Washington Washington University, St. Louis France IN2P3, CEA/Saclay Italy INFN, ASI Japanese GLAST Collaboration Hiroshima University ISAS, RIKEN Swedish GLAST Collaboration Royal Institute of Technology (KTH) Stockholm University PI: Peter Michelson(Stanford & SLAC) ~225 Members (including ~80 Affiliated Scientists, plus 23 Postdocs, and 32 Graduate Students) Cooperation between NASA and DOE, with key international contributions from France, Italy, Japan and Sweden. Managed at Stanford Linear Accelerator Center (SLAC).

  3. GLAST is a NASA/DOE Mission • Launch: Feb-April 2008 • Lifetime: 5-years (10-years goal) • Orbit: 565 km, circular • Inclination: 28.5o Large Area Telescope (LAT) 20 MeV - 300 GeV • GLAST is the next generation after EGRET… factor > 30 improvement in sensitivity • Large effective area, factor > 5 better than EGRET • Field of View ~20% of sky, factor 4 greater than EGRET • Point Spread function factor > 3 better than EGRET for E>1 GeV. On axis >10 GeV, 68% containment < 0.12 degrees • Smaller deadtime. • Minimize rejection of E>10GeV gamma rays due to backscatter into cosmic ray shield • No expendables (EGRET had spark chamber gas) - long mission without degradation (5-10 years) GLAST Burst Monitor (GBM) 5 keV - 25 MeV

  4. Basics of a pair conversion telescopes Basic structure of a pair conversion telescope Tracker/converter (detection planes + high Z foils): photon conversion and reconstruction of the electron/positron tracks. Calorimeter: energy measurement. Anti-coincidenceshield (ACD): backgound rejection (cosmic rays flux ~104 higher than the gamma flux). Signature of a gamma event: No ACD signal 2 tracks (1 Vertex)* Calorimeter signal (~Energy) Anticoincidence shield Conversion foils Particle tracking detectors e+ e– Calorimeter

  5. GLAST Large Area Telescope (LAT)  e+ e– • Anti-Coincidence Detector • 4% R.L. • 89 scintillating tiles • efficiency (>0.9997) for MIPs 1.8 m • Tracking detector • 16 tungsten foils (12x3%R.L.,4x18%R.L.) • 18 pairs of silicon strip arrays • 884736 strips (228 micron pitch) 1.0 m • Calorimeter • 8.5 radiation lengths • 8 layers cesium iodide logs • 1536 logs total (1200kg) One of the biggest Silicon Tracking systems ever constructed.

  6. GEANT4 detector simulation High-energy g interacts in LAT Geometry Detail Over 45,000 volumes, and growing! Interaction Physics QED: derived from GEANT3 with extensions to higher and lower energies (alternate models available) Hadronic: based on GEISHA (alternate models available) Propagation Full treatment of multiple scattering Medium-dependent range cut-off Surface-to-surface ray tracing. Includes information from actual LAT tests detailed instrument response dead channels noise etc. Overall Deadtime Effects Black: Charged particles White: Photons Red: Deposited energy Blue: Reconstructed tracks Yellow: Inferred γ direction F. Longo

  7. Expected GLAST-LAT Performance Angular resolution of better than 1 degree at energies > 1 GeV Angular resolution of better than 0.2 degree at energies > 10 GeV Better than 10% energy resolution for 100 MeV through 100 GeV About 5% around 1 GeV

  8. GLAST Science 0.01 GeV 0.1 GeV 1 GeV 10 GeV 100 GeV 1 TeV Active Galactic Nuclei Solar flares Unidentified sources Cosmic ray acceleration Pulsars Gamma Ray Bursts Quantum Gravity ? Dark matter thanks: N. Omodei

  9. Gammas from lines For gg Line, energy = WIMP mass For WIMP masses > MZ /2 can also have gZ0 line Measurement of line branching fractions would constrain particle theory γ γ c c c c γ Z0 time Branching fractions are in the range 10-2 - 10-4

  10. Background to all photons: charged particles Black, total; light green, GCR protons; lavender, GCR He; red, GCR electrons; blue, albedo protons; light blue, albedo positrons; green, albedo electrons; and yellow albedo gammas. - Final rejection power: 1/106 -γ efficiency: 0.8 Sreekumar et al. Astrophys.J.494:523-534,1998 • Strong et al. Astrophys.J.613:956-961,2004 T. A. Porter et al. 30th ICRC, Merida, Mexico

  11. Galactic diffuse: conventional and optimized GALPROP model ’conventional’ GALPROP: calibrated with locally measured electron and proton,helium spectra, as well as synchroton emission Optimized GALPROP: Conventional Optimized Strong, Moskalenko, Reimer, ApJ537, 736, 2000 Strong, Moskalenko, Reimer, ApJ613, 962-976, 2004

  12. Dark Matter in the gamma ray sky Milky Way Halo simulated by Taylor & Babul (2005) All-sky map of DM gamma ray emission (Baltz 2006) Galactic center Milky Way satellites Milky Way halo Extragalactic Only dm annihilation radiation shown….

  13. Several Different Search Modes

  14. WIMP annihilation: gamma-ray flux

  15. WIMP annihilation: gamma-ray yield Gamma ray yield per final state bb 200GeV mass WIMP WIMP pair annihilation gamma spectrum

  16. Galactic Center ROI: 1.0 degree GC, E > 1 GeV 4 years of operation Simulate Particle-yield (DarkSUSY) Simulate GLAST response (ObsSim) Assume background given by conventional/optimized galprop model Check if WIMP + background can be distinguished from background only (using χ2 for simplicity). 1 GeV 10 Gev

  17. Dark Matter From the Galactic Center E. Nuss, A. Lionetto, A. Morselli

  18. Senstivity to lines: where to look

  19. Line 5σ sensitivity Simulated detector response to δ function in energy 10-8 5 Years Worth of data Average χ(bootstrapped) > 25 10-9 Y. Edmonds, E. Bloom, J. Cohen-Tanugi

  20. Example: Dark Matter Satellites 55-days GLAST in-orbit counts map (E>1GeV) Galactic Center Optimistic case: 70 counts signal, 43 counts background within 1.5 deg of clump center 30-deg latitude

  21. Semi-analytic models of halo substructure1) Signal, background flux inside the tidal radius WIMP mass = 100GeV Satellites/Subhalos P. Wang, L. Wai, E. Bloom How many sources at which signficiance ? 100 GeV WIMP, 10 σ detection No. of satellites GLAST 5-yrs <σannihv >[2.3e.-26 cm-3s-1] GLAST 1-yr Green: optimized Red: conventional WIMP mass [GeV] Significance [ σ] • Taylor & Babul, MNRAS, 364, 535 (2004) - MNRAS, 364, 515 (2005) -MNRAS, 348, 811 (2004)

  22. Galactic Halo Analysis Use the large statistics of the full sky. Remove the Galactic Center (<10o) from consideration Consider a range of Neutralino Masses Perform a simulaneous fit to both the energy and spatial distribution. Measure the sensitivity to observing a signal. Mass vs <s v> 1 year of running A. Sander, R. Hughes, B. Winer

  23. Sensitivity for Galactic Halo Analysis <s v> cm3-s-1 A. Sander, R. Hughes, B. Winer

  24. Acknowledgements E. Bloom, Y. Edmonds, P. Wang, L. Wai, J. Cohen-Tanugi(SLAC/KIPAC) I. Moskalenko (Stanford) A. Morselli, A. Lionetto (INFN Roma/Tor Vergata) E. Nuss (Montpellier) R. Hughes, A. Sander, B. Winer (Ohio State) L. Bergström, J. Edsjö, A. Sellerholm (Stockholm) A. Moiseev (Goddard)

  25. Launch Early 2008! Summary • GLAST will shed light on the multi-GeV EGRET data. • The GLAST LAT team is pursing complementary searches for signatures of particle dark matter. • These analyses will continue to be optimized over the next 4-6 months prior to launch. • We are looking forward to launch and adding a new piece to the puzzle of dark matter.

  26. 1st International GLAST symposium, Stanford, USA (Feb 2007) L. Bergström, J.C., J. Edsjö, A. Sellerholm: Cosmological WIMPs G. Bertone, T. Bringmann, R. Rando, A. Morselli : Point sources A. Lionetto: mSUGRA and ED from the Galactic Centre A. Morselli, A. Lionetto, E. Nuss: Galactic Centre Y. Edmonds, E. Bloom, J. C. , J. Scargle, L. Wai: Line sensitivity A. Sander, B. Winer, R. Hughes, L. Wai: Halo sensitivity L. Wai : Overview P. Wang, E. Bloom, L. Wai: Galactic Satellites Summary Paper in preparation More Information... http://glast.gsfc.nasa.gov/science/symposium/2007/program.html

  27. BACKUP SLIDES

  28. Extra Higgs-Doublet, additional symmetry,Z2(Ho ) (Inert Doublet Model, Barbieri et. al. PRD 74 (2006) ) one could think the model was designed for GLAST ... It wasn’t. Inert Higgs Dark Matter Gustaffson et. al. astro-ph/0703512

  29. Generic WIMP flux • γ yield per annihilation • Flux from given source ISASUGRA line continuum Annihilation cross setcion. Constraint by cosmology to ~ 10-26 cm2 Dark Matter structure

  30. ”Optimized model”: allow average CR spectrum to deviate from local spectrum Modify antiprotons and electrons Background to WIMP signal: galactic diffuse(slide from Igor Moskalenko)

  31. Jan Conrad (KTH, Sthlm) La Thuile March 200733 Identification of Dark Matter subhalos 5 yr GLAST, single clump, 1 degree rejected Molecular cloud rejected 200 GeV WIMP 30 GeV WIMP rejected allowed Pulsar Baltz, Taylor, Wai, astro-ph/0610731

  32. mSUGRA exclusion (Galactic Center) A0 = 0 Similar ”analysis” as in generic WIMP case 5yr, 3σ discovery trunc. NFW Acc. Limits: Baer et al. hep-ph/0405210 A.Morselli, E. Nuss, A. Lionetto. First Glast Symposium, 2007 Jan Conrad (KTH, Sthlm) Scineghe07 June 200734

  33. tang  = 60 A0 = 0

  34. Sagittarius

  35. EGRET excess: Disk surface mass density within 0.8 kpc • - Allowed density within 0.8 kpc of the disk 57 – 66 M (Sun) /pcsqr from observations • Stars ~ 40 M(Sun)/pc^2 • ISM ~ 13 M(Sun)/pc^2 • DM ~ 4- 16 M(Sun)/pc^2 • de Boer: 29 M(Sun)/pc^2 Bergström et. Al. JCAP05(2006)006

  36. EGRET excess: anti-protons Anti protons from a SUSY model yelding good fit to EGRET data Spread due to uncertainty in propagation Bergström et. Al. JCAP05(2006)006

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