indirect dark matter search with ams
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6emes Rencontres du Vietnam, Hanoi 9-Aug-2006
T. Siedenburg for the AMS Collaboration
Indirect Dark Matter Search with AMSCosmic Ray Astrophysics with AMS02 – PS1 D.Haas
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 2
Cosmic Puzzle
Precision Cosmology
WMAP CMB Power SpectrumSDSS 3D Matter SpectrumHubble SN-Ia Redshift
Clues in CR Spectra ?
1/s/GeV
1/d/GeV
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 3
Detecting a SUSY Neutralino as Dark-Matter Candidate
WIMP: Weakly Interacting Massive ParticleStructure: Cold Dark-Matter
Direct Detection
current local density SD/SI
Visible Matter
GC
Indirect Detection: Neutralino-Annihilation
solar lifetime average
Dark Matter Halo
AMS02 Dark-Matter Detection
Spectrum/Line from GC
Charged Anti-Particles1GeV-1TeV: 5 kpc Sphere
(prop.)gm/ v ~Flux
Solar/terrestrial neutrinos
e
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 4
Dark Matter Detection Requirements
Signal propagation and BackgroundGalactic Models and Solar Modulation
Nuclear abundance: B, C, 10Be, 9Be, ...Standard particles: e, pSecondary prod.: e, p
Tracking + charge / isotope separation
Signal from WIMP annihilationParticle Generators & DM Density
Contributions to : e, p, , D
Proton supression by 106
Electron supression by 104
Gamma reconstruction (energy / angle)
e+
e+ + e–
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 5
AMS01 Precursor FlightSTS-91 2.-12.JUN 1998
Permanent Magnet 0.15 Tm2
6 Si-Strip Tracker Planes4 Sc-Panel TOF Trigger LayersAerogel Čerenkov + Veto ACC
108 Events in 10 days
AMS01
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 6
Proton Suppression:Bremsstrahlung ~ 1/m2
1
2
AMS01 Positron Selection above 3.5 GeV
• 3 track events with converted middle track from primary e
• Efficient track reconstruction
• Reject high dE/dX |Q|>1 events
• Keep backtraced extraterrestrial events
• Background e– with wrong charge p p + –
p p 0 p e+e– ()
Reconstruct invariant masses at radiation and conversion vertex
TOF 1
TOF 2
TOF 3
TOF 4
@ @
Primary Positron
Photon
SecondaryPositron
SecondaryElectron
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 7
Selected AMS01 PositronsProton MC
Geomagnetic Cutoff
Spectral Index
118 Selected 24.9 Protons 6.5 Electrons
Background from p and e MCReweight for geomagnetic cutoff
spectral indexScale to measured p and e flux
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 8
Acceptance and Livetime Corrections for Flux Calculation
“Upward” Shuttle Floor
For each 4sec Flight Period * Get Shuttle Coordinates * Backtrace particle in 9 cos8 8 p bins * Sum DAQ livetime for extraterrestrial tracksSeparately up/down e+/e–
5000 CPU Days
d/ dE = N / (A ∙ T ∙ E)
Geometrical Acceptance A Average Livetime T
Trapped Particle
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 9
AMS01 Lepton Fluxes AMS01 Positron Fraction
J.Olzem, H.Gast
J.Olzem, H.Gast
Cancellation of systematics in fraction( Detector acceptance / Livetime )
e+
e+ + e–
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 10
Improve with AMS02
TRD Xe/CO2 Straws
p+rej. >102 1-300 GeV 0.5m2sr
TOF Trigger (2up+2low)
t: = 120ps: dE/dX: Z
Superconducting Magnet0.8 Tm2 2.5t superfluid He
Silicon Strip Tracker 6m2
p up to 1TV and Z(dE/dX)
RICH Aerogel/NaF3 Sep. A~26 1-12 GeV + Z
ECAL 3D lead/scint-fibreh rej. >103 1-300 GeV 0.05m2sr
3m 6700 kg
3.5m
3 years above atmosphere
Tracking and Particle ID
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 11
Charge / Isotope Separation
0
dE/dX from TrackerRICH (and TOF)
TRD Positron Proton Separation
from RICH (1-12 GeV/n)
1 Layer
20 Layer TRD Beamtest
A/Z = 2 GSI Beamtest
Momentum from Trackerwith Supercond. Magnet Mass for Isotope Sep.
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 12
ECAL 16.4 X0 18 x/y samplings
Star Tracker: 30“
ECAL
Energy and angle 1 GeV – 1 TeVh/e Separation: 103 shower-shapeAcceptance: 0.05m2sr
Conversion
0.4 X0
AMS02 GAMMA DETECTION
Angular Resolution / deg
E / GeV E / GeV
Energy Resolution / %
E / GeV
Effective Area / cm2
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 13
AMS02 Nuclei and Isotopes
B/C
105 C 104 B > 100 GeV/n in 3 years 105 10Be 0.5-10 GeV in 3 years
AMS02 MC
10Be / 9Be
Determine Propagation Model Parameter Errors from Variation with AMS02 MC Error Estimation
E / GeV/n
NaF
Agl
Secondary/Primary: Traversered MatterUnstable/Stable: Confinement Time
TOFE / GeV/n
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 14
4x106 AMS02 Positrons from 5-300 GeV
Proton Rejection 106
from TRD 1000-100 ECAL 100-1000 E/p 10
Improve precision of SM background predictionto enhance sensitivityfor subtle deviations within the same dataset
e.g. WIMP annihilations…
e+
e+ + e–
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 15
Test of mSUGRA parameter space with precise positron fraction
E / GeV
E / GeV
E / GeV
Constraints: g-2 mh CDM
bs BS+–
mt=175.2GeV mb=4.2GeV s=0.1187
Fixed: A0 = 0 sign() = +1
Free: m0 m1/2 tan
E / GeV
Focus Point Rapid Funnels
Bulk Point Co-Annihilation
BF 1.7e5
BF 1.2e5BF 3.2e3
BF 6.1e3
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 16
AMS02 Antiprotons and Gammas
106 Antiprotons 0.5-100 GeV
Electron Rejection 104 from TRD + ECAL + E/p
(3 years)
p
Sensitivity: 7x10-9 / cm2 / s
1 GeV EGRET Excess and de Boer DM ring interpretation hard to confirmCuspier Halo-Profile: flux x10
A.Jacholskowska et al.Phys.Rev.D 74 023518 (2006)
Ro = 8.0 kpc, 0 = 0.3 GeV/cm3, a = 20 kpc
Antiprotons sensitive to solar modulation
m0 = 60 GeV
m1/2 = 250 GeV
A0=0 tan=10 >0
LIS + Geomagn.cutoff
BF 2.0e1 from
gal
acti
c ce
nter
Hanoi 9-Aug-2006
T. Siedenburg AMS Dark-Matter 17
Conclusion AMS Dark-Matter Detection
Tracking – 3 TV RICH 1 – 12 GeVCalorimetry 1 GeV – 1 TeV TRD 1 – 300 GeV
High statistics e, p and AZto tune cosmic models
e, p, and spectra forcombined dark-matter fit
AMS02: Complete, large acceptance, 3 years above atmosphere
Shuttle isback to flight
AMS02 is on schedule for flight in 2009
AMS01: Successful flight, HEAT Positron excess not excluded
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