IceCube Galactic Halo Analysis

1. IceCube Galactic Halo Analysis Carsten Rott Jan-Patrick Huelss CCAPP Mini Workshop Columbus OH August 6, 2009 1450 m 2450 m CCAPP DM Miniworkshop

2. IceCube Detector and DeepCore Ereco= 500 TeV 1450 m Dust concentration 2450 m Very clear ice CCAPP DM Miniworkshop

3. General Detector Capabilities Muon from IC40 Data Cascades Tracks IceCube Angular Resolution < 1° 3 CCAPP DM Miniworkshop

4. Dark Matter Searches CCAPP DM Miniworkshop

5. Annihilation rate ∝r 2 Halo WIMPs • Galactic Center on Southern hemisphere -30o • Requires identification of down-going starting events • Neutrino signal “least detectable”, hence allows to set conservative limit on the total self-annihilation cross-section [Yuksel, Horiuchi, Beacom, Ando (2007)]‏ CCAPP DM Miniworkshop

6. Halo WIMPs A neutrino flux from annihilations in the Milky way halo might be observable as neutrino flux anisotropy. Use up-going tracks (from the Northern hemisphere) to have access to TeV range neutrinos. Galactic center: cos(y)=1 (B=0,L=0)‏ q Example: 10 degree zenith angle band mapped in galactic coordinates Preliminary Df Df CCAPP DM Miniworkshop RA(f)‏ [L=0,B=0]

7. What to look for ? Preliminary CCAPP DM Miniworkshop

8. Deep Core Extension • Deep Core Strings • 6 strings with high quantum efficiency PMTs, densely spaced • 7 “standard” IceCube strings • located in best ice (below 2100 m exceptionally clear)‏ • Interstring spacing 72m • Uses high Quantum Efficiency PMTs, that have about 40% higher efficiency • Located in the deep ice • Lower atmospheric muon background • Larger scattering length ~40m CCAPP DM Miniworkshop 8 8

9. Effective Area Fermi CCAPP DM Miniworkshop arXiv:0810.3698 9 9

10. Conclusions IceCube DarkMatterHalo Analysis underway using Northern Hemisphere with 22 string dataset Access to Southern Hemisphere with IceCube 40 and DeepCore will significantly improve sensitivity IceCube Neutrino Effective Area not so different from Fermi Conclusions CCAPP DM Miniworkshop

11. Motivation Spin-dependent WIMP-proton cross-section gap Spin-dependent WIMP-nucleon cross-section very difficult to access in direct detection experiments CCAPP DM Miniworkshop

12. Solar WIMPs Solar WIMPs  Search for an excess neutrino flux from the direction of the sun Analysis performed with the IceCube 22 string detector and 104 days of livetime(when the sun below the horizon) • Cold Dark Matter candidate particle is assumed to be the LSP (neutralino) in MSSM, R-parity conserving scenario • Neutralino is a Majorana particle and self-annihilates • Consider two annihilation channels: • Hard: cc → W+ W–→ n n • Soft: cc→ bb → n n • Consider 7 neutralino masses from 50 GeV to 5 TeV Preliminary CCAPP DM Miniworkshop

13. c nm Cross-section Limits nm Solar capture rate: WIMP Annihilation Rate: (for equilibrium): or CCAPP DM Miniworkshop July 8, 2009 Carsten Rott - ICRC09 Lodz 13

14. Solar WIMPs • Look for an excess of (muon) neutrinos in the direction of the sun • No evidence for a signal observed • Upper limits on muon flux from neutralino annihilations in the Sun Preliminary Preliminary • Under the assumption of equilibrium condition in the Sun, a limit on the WIMP-Nucleon cross-section can be obtained • For spin-dependent couplings, IceCube’s sensitivity is about 2-orders of magnitude better than direct searches arXiv: 0902.2460 (PRL 102, 201302) CCAPP DM Miniworkshop

15. Solar WIMPs (AMANDA Limits and Future Prospects) Preliminary CCAPP DM Miniworkshop

16. Earth WIMPs Earth WIMPs • Dark Matter could be clustered in the centre of the Earth • Annihilation signal might be observable in vertically up-going events • AMANDA analysis on-going • IceCube analysis on-going • Understanding of low energy vertical tracks extremely important Energy and zenith angle of muon neutrino events in the signal region (see also “Search for Atmospheric Oscillations with IceCube”) CCAPP DM Miniworkshop

17. Earth WIMPs Beginning with 40 string data, IceCube lowered the multiplicity 8 trigger threshold to 5 applying a string trigger Preliminary Preliminary String Trigger: 5 DOMs hit within a series of 7 DOMs within a time window of 1500ns  CCAPP DM Miniworkshop

18. Spin Independent Result • Under the assumption of equilibrium condition in the Sun (and the assumption that capture is dominated by spin-independent cross-section), a limit on the WIMP-Nucleon cross-section can be obtained • IceCube limits are competitive with direct detection experiments at WIMP masses, where IceCube is sensitive CCAPP DM Miniworkshop

19. New stringent limit on the WIMP-nucleon scattering cross-section using IceCube 22-string data DeepCore combined with IceCube will allow to probe a large region of SUSY parameter space that is difficult to access in direct detection experiments Preliminary CCAPP DM Miniworkshop

20. IceCube Detector Status 07/08 IC22 06/07 IC40 IC40 IC22 DeepCore 09/10 05/06 08/09 10/11 04/05 CCAPP DM Miniworkshop

21. Solar WIMP analysis Systematic uncertainties on the effective volume: • Neutrino oscillation: 4% • Neutrino-nucleon cross-section: 3% • Muon propagation in ice: <1% • Proton propagation & absolute OM sensitivity: 17-24% • Spread in OM sensitivity: <5% • Time & position calibration: <5% • Signal MC statistics: 3-5% Total systematic uncertainty: 19-26% Preliminary CCAPP DM Miniworkshop