Indirect Dark Matter Search with AMS Cosmic Ray
- Slides: 17
Indirect Dark Matter Search with AMS Cosmic Ray Astrophysics with AMS 02 – PS 1 D. Haas T. Siedenburg for the AMS Collaboration 6 emes Rencontres du Vietnam, T. Siedenburg Hanoi 9 -Aug-2006 AMS Dark-Matter
Cosmic Puzzle Clues in CR Spectra ? Precision Cosmology 1/s/Ge. V WMAP CMB Power Spectrum SDSS 3 D Matter Spectrum Hubble SN-Ia Redshift 1/d/Ge. V Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 2
Detecting a SUSY Neutralino as Dark-Matter Candidate Structure: Cold Dark-Matter WIMP: Weakly Interacting Massive Particle Visible Matter Dark Matter Halo Direct Detection current local density SD/SI Indirect Detection: Neutralino-Annihilation GC Solar/terrestrial neutrinos solar lifetime average g AMS 02 Dark-Matter Detection Spectrum/Line from GC e Hanoi 9 -Aug-2006 Charged Anti-Particles 1 Ge. V-1 Te. V: 5 kpc Sphere T. Siedenburg AMS Dark-Matter 3
Dark Matter Detection Requirements Signal propagation and Background Galactic Models and Solar Modulation Nuclear abundance: B, C, 10 Be, 9 Be, . . . Standard particles: e, p Secondary prod. : e, p Tracking + charge / isotope separation Signal from WIMP annihilation Particle Generators & DM Density Contributions to : e+ e+ + e – e, p, g, D Proton supression by 106 Electron supression by 104 Gamma reconstruction (energy / angle) Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 4
STS-91 2. -12. JUN 1998 AMS 01 Precursor Flight Permanent Magnet 0. 15 Tm 2 6 Si-Strip Tracker Planes 4 Sc-Panel TOF Trigger Layers Aerogel Čerenkov + Veto ACC 108 Events in 10 days AMS 01 Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 5
AMS 01 Positron Selection above 3. 5 Ge. V Proton Suppression: Bremsstrahlung ~ 1/m 2 TOF 1 TOF 2 • 3 track events with converted g middle track from primary e • Efficient track reconstruction Primary Positron • Reject high d. E/d. X |Q|>1 events • Keep backtraced extraterrestrial events q 1 • Background Photon q 2 e– with wrong charge p p p+ p– p p p 0 p e+e– (g) Reconstruct invariant masses at radiation and conversion vertex @ @ TOF 3 TOF 4 Secondary Positron Hanoi 9 -Aug-2006 Secondary Electron T. Siedenburg AMS Dark-Matter 6
Selected AMS 01 Positrons Proton MC Background from p and e MC Reweight for geomagnetic cutoff spectral index Scale to measured p and e flux Geomagnetic Cutoff 118 Selected 24. 9 Protons 6. 5 Electrons Spectral Index Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 7
Acceptance and Livetime Corrections for Flux Calculation d. F / d. E = N / (A ∙ T ∙ DE) “Upward” Shuttle Floor For each 4 sec Flight Period * Get Shuttle Coordinates * Backtrace particle in 9 cosq, 8 j, 8 p bins * Sum DAQ livetime for extraterrestrial tracks Separately up/down e+/e– 5000 CPU Days Geometrical Acceptance A Hanoi 9 -Aug-2006 T. Siedenburg Trapped Particle Average Livetime T AMS Dark-Matter 8
AMS 01 Lepton Fluxes J. Olzem, H. Gast AMS 01 Positron Fraction e+ e+ + e – J. Olzem, H. Gast Cancellation of systematics in fraction ( Detector acceptance / Livetime ) Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 9
Improve with AMS 02 3 m 6700 kg 3. 5 m Tracking and Particle ID TRD Xe/CO 2 Straws p+rej. >102 1 -300 Ge. V 0. 5 m 2 sr TOF Trigger (2 up+2 low) st: = 120 ps: b d. E/d. X: Z Superconducting Magnet 0. 8 Tm 2 2. 5 t superfluid He Silicon Strip Tracker 6 m 2 p up to 1 TV and Z(d. E/d. X) RICH Aerogel/Na. F 3 s Sep. A~26 1 -12 Ge. V + Z ECAL 3 D lead/scint-fibre h rej. >103 1 -300 Ge. V 0. 05 m 2 sr 3 years above atmosphere Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 10
Charge / Isotope Separation TRD Positron Proton Separation d. E/d. X from Tracker RICH (and TOF) A/Z = 2 GSI Beamtest 1 Layer 0 20 Layer TRD Beamtest b from RICH (1 -12 Ge. V/n) Momentum from Tracker with Supercond. Magnet Mass for Isotope Sep. Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 11
AMS 02 GAMMA DETECTION ECAL 16. 4 X 0 18 x/y samplings 0. 4 X 0 Effective Area / cm 2 Energy and angle 1 Ge. V – 1 Te. V h/e Separation: 103 shower-shape Acceptance: 0. 05 m 2 sr ECAL Conversion E / Ge. V Angular Resolution / deg Energy Resolution / % Star Tracker: 30“ E / Ge. V Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter E / Ge. V 12
AMS 02 Nuclei and Isotopes Secondary/Primary: Traversered Matter Unstable/Stable: Confinement Time 105 C 104 B > 100 Ge. V/n in 3 years Determine Propagation Model Parameter Errors from Variation with AMS 02 MC Error Estimation 105 10 Be B/C 0. 5 -10 Ge. V in 3 years 10 Be / 9 Be Agl Na. F E / Ge. V/n Hanoi 9 -Aug-2006 T. Siedenburg TOF AMS Dark-Matter AMS 02 MC E / Ge. V/n 13
4 x 106 AMS 02 Positrons from 5 -300 Ge. V Proton Rejection 106 from TRD 1000 -100 ECAL 100 -1000 E/p 10 e+ e+ + e – Improve precision of SM background prediction to enhance sensitivity for subtle deviations within the same dataset e. g. WIMP annihilations… Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 14
Test of m. SUGRA parameter space with precise positron fraction Constraints: gm-2 b sg Focus Point mh WCDM + BS m m– Rapid Funnels mt=175. 2 Ge. V mb=4. 2 Ge. V as=0. 1187 Fixed: A 0 = 0 sign(m) = +1 Free: tanb m 0 m 1/2 BF 1. 7 e 5 E / Ge. V Bulk Point BF 3. 2 e 3 Hanoi 9 -Aug-2006 T. Siedenburg BF 6. 1 e 3 E / Ge. V Co-Annihilation E / Ge. V AMS Dark-Matter BF 1. 2 e 5 E / Ge. V 15
AMS 02 Antiprotons and Gammas Electron Rejection 104 from TRD + ECAL + E/p 1 Ge. V EGRET Excess and de Boer DM ring interpretation hard to confirm Cuspier Halo-Profile: flux x 10 106 Antiprotons 0. 5 -100 Ge. V Sensitivity: 7 x 10 -9 / cm 2 / s Antiprotons sensitive to solar modulation m 0 = 60 Ge. V m 1/2 = 250 Ge. V A 0=0 tanb=10 p from galactic center LIS + Geomagn. cutoff Ro = 8. 0 kpc, r 0 = 0. 3 Ge. V/cm 3, a = 20 kpc m>0 BF 2. 0 e 1 A. Jacholskowska et al. Phys. Rev. D 74 023518 (2006) (3 years) Hanoi 9 -Aug-2006 T. Siedenburg AMS Dark-Matter 16
Conclusion AMS Dark-Matter Detection AMS 01: Successful flight, HEAT Positron excess not excluded AMS 02: Complete, large acceptance, 3 years above atmosphere Tracking Calorimetry – 3 TV 1 Ge. V – 1 Te. V High statistics e, p and AZ to tune cosmic models Shuttle is back to flight Hanoi 9 -Aug-2006 RICH TRD 1 – 12 Ge. V 1 – 300 Ge. V e, p, and g spectra for combined dark-matter fit AMS 02 is on schedule for flight in 2009 T. Siedenburg AMS Dark-Matter 17
