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