V' Zhukov University of Karlsruhe, IEKP

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Astroparticle Physics with AMS02
V.Zhukov University of Karlsruhe and INP MSU on
behalf of AMS Collaboration

• Modern Cosmology and Particle Physics
• AMS02 detector technological challenge
• Detecotor performance
• Discovery potential

11th Lomonosov Conference, August 2003, Moscow
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02
NASAHEP community experiment scheduled
for 2006-2009 mission on board of ISS. The only
general purpose experiment at ISS
INP MSU
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Modern Cosmology Main observations

• 1929 Hubble constant
• HV/R H 100h 0 km/s Mpc h 00.710.03
• rc 3H 2 /8pG Wr/rc WtotWL WM
• t univers 1/H 0 14 Gyr
• Expanding Universe dominated by Dark Energy L

• 1963 Cosmic Microwave Background (CMB)
• T2.725 0.001K
• 2002 CMB anisotropy by WMAP
• Wtot WL W DarkMatter W
  BaryonicMatter
• 1.020 .02 0.730. 04 0.230. 04
  0.0440. 004
• t stars 200 Myr t univers 13.7
  0.2 Gyr
• Flat Universe
  

WMAP CMB anysotropy
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Modern Cosmology Main observations

• Rotation curves of spiral galaxies
• v 2GM(r)/r const r(r)3v2/4pGr2
• W DMhalo gt 10 W visible W visible lt 0.005
• Dark Matter halo

• Abundances of elements
• From primordial nucleosynthesis
• 0.16 gt W baryon gt 0.015
• h N baryons / N g 3-7 10 -10 (expected
  10 -18)
• Baryon asymmetry and baryogenesis

• Structure of the Universe
• Dark Matter dominated structure formation.

• Cosmic ray spectrums
• Production and propagation of cosmic particles

Etc.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Particle Physics

• Standard Model (SM)
• N n 2.98 m Higgsgt115 GeV etc.
• But fine tunning and hierarchy problems.
  Solution
• SUSY models
• QBosongtFermiongt solves SM problems
• Heavy superpartners for SM particles
• Rparity conservation requires stable LSP which
• weakly interacts with normal matter
• Provides coupling constant unification
• Includes gravity symmetry breaking
• mSUGRA, MSSM , ...

• Quantum gravity
• String theory, Extra Dimensions?

V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Theory ingredients
Dark Energy
Baryogenesis
Big Bang
Structure formation
Inflation
Dark Matter
Primordial nucleosynthesis
SUSY GUT
BigBang as a quantum fluctuation governed by the
DarkEnergy (repulsive gravity) Inflation -
phase transition in the GUT. Fast expansion of
the Universe at t10 -35s R(t) e
Ht DarkMatter is freezed out (G ltH) at t 10
-10 s and can be seen now as a
relic. Nucleosynthesis starts at 1 min and
produces most of H and He. Baryogenesis
explains Baryon asymmetry . No antimatter now
days. (baryon number
violation C and CP violation out of
equilibrium decay ) Structure formation is
determined by the density fluctuations of DM
after freeze out. Baryonic
matter joints the formation
after decoupling from radiation (last scattering)
Can we see Dark Matter?
Antimatter?
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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History of the Universe
?
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Constrained Minimum SuperSymmetric
Model (CMSSM)
Evolution of mass spectrum from Renormalization
group equation (RGE)
Main parameters A o, m1/2 , m o , tanb,
m LSP is a bino-like neutralino m c 0.4
m1/2 m c gt 120 GeV neutralino is a spin ½
Majorana particle and can annihilate Dark
Matter candidate N 1. Constrains from GUT
coupling unification and Electroweak Symmetry
breaking (EWSB) preferable solution with tan b
gt30 and A00
,
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Constrained Minimum SuperSymmetric
Model (CMSSM)
Accessible region (blue) for mo-m1/2 plane
constrained by a) LEP limit on Higgs mass
gt114 GeV b) LSP is neutralino. Light blue band is
preferred from CMB anisotropy data (WMAP)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures cross sections
Annihilation of neutralino
1. Tree diagrams
quarks hadronize to hadrons p, pbar , e, e-
, g are stable and can reach the Earth with
continuum energy spectra
2. 1 loop diagrams
...
Monochromatic lines E g m c , m c -mz2/4mc
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures cross sections

• Sfermion, Z and Higgs exchange
• cross section is proportional to mf2
• Heavy fermions dominate
  Neutralino annihilates at T c 2K , pcms 0
• light fermions are suppressed
• at tanb gt5 t t is suppressed

c oc o -gtb b is a dominant exchange
determines the spectrum of signal
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures cross section
Effective thermal average cross section lt seff
Vgt A/n2 A -annihilation rate, n-equilibrium
density Dependence on m 0 , m1/2 and tan b (
mc 0.4 m ½ , s mc-4 )
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures
Cosmic ray spectra is dominant by stable
particles from nuclear interactions p, He,
e- Have chance to see positron, antiproton and
gamma component from neutralino annihilation
where background is smaller. Energy range should
be comparable with mc

Flux for i -component is
lt seff Vgt is calculated from CMSSM Halo
profile ? Propagation ?
Background cosmic ray spectra
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures halo profile
From rotation curves neutralino is spherically
distributed with the peak at galactic
center. Navarro, Frenk, White type Dark Matter
halo profile
(a,b,g) - define the slope r0 - local density
0.3-0.7 GeV/cm3 a -scale parameter (depends
on r0) integrate r2 (r) along line of
sight l r2 l2r02-2lr0cos f
Local 'clumps ' of DM can significantly
increase signal from the neutralino annihilation
(boost factors)
We are here ro8kpc

V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures propagation

• Propagation (diffusion in interstellar media
  with magnetic field 4 mG ,
  spallation, reacceleration,
  etc)
• Background production (supernova, pulsars,
  black holes, etc)
• Secondary particle production (nuclear
  interactions)
• Solar activity effects, modulation

The propagation parameters can be fixed from
isotopes abundances.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures propagation model

• Important parameters
• Dxx b Do p a a0.3 Do diffusion coefficient
  , defined from B/C ratio.
• size of the galactic disk Rh30kpc, zh4-12
  kpc
  (propagation time)
  defined from 10Be/ 9Be ratio
• va - Alfven speed for reacceleration models
• 20km/s for zh5kpc.
• Nucleur cross sections has to fit observed
  element
• abundances p-gtC,N,O-gtBe,B, antiprotons, e-
  etc.
• Size of interstellar gas and density of
  hydrogen.
• Solar modulation parameters F350-1200MV

Problems in model
To few antiprotons, gamma and positrons are
predicted
B secondary produced in nuclear interactions and
spallation, C -primary produced in starts
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Signal signatures propagation model

• Gamma propagates without (almost) interactions
  but needs to be in detector acceptance,
  therefore smaller contribution.
• Positrons and Antiprotons diffuse 5- 8 g/cm2
  before reaching the Earth. Positrons
• travels smaller distances due to large losses.

Fluxes per annihilation produced in the source
(galactic center) and after propagation.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 technolgical challenge
Total weight 7
t Size
3.2 x 2.7 m Power consumption
2 kW Superconductive magnet Bdipole
0.8 Tesla
(d1.2m l0.8 m) He cooled (2500l)
1.8K Operation Temperature -180o
50oC Data rate
1 Mb/s Acceleration
9 g
Installed on International Space Station (ISS)
400km orbits 2006 for 3 Years
(without assistance)
1998 AMS01 precursor flight on board of
Discovery (100h ) with permanent magnet 0.15T
and Tracker
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 technolgical challenge
Transition Radiation Detector 20 layers of 6mm
straw tubes(5248) filled with Xe/Co2 (44 kg
Xe3.7kg Co2) fleece radiator
(20mm) Separation e/h 10 3 p1-250 GeV
Time of Flight 2x2 planes of scintillator
hodoscope DT120 ps , b and dE/dx
measurements,ToF used in Trigger
Tracker in B0.8T 8 planes of double sided
Silicon (7 m2). s 17 m in bending plane(30 m
other), dE/dx measurement. Rigidity p/ze
measurements up to 3 TeV
Anticoincidence veto plastic scintillators used
in Trigger
Ring Image Cherenkov Detector radiator PMT's
b (up to 20 GeV 0.1) and charge Z
measurements (s0.2) ions identification
Electromagnetic Calorimeter Pb with
scintillators fibers readout by PMT's. Overall 18
x-y planes 68x68 cm2 Thickness 15 Xo and
0.5 lnucl. Electron(gamma) hadron separation
10 3
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 detector performance
Number of events of i - component measured by
AMS02 is N tot i F(signal)i A(signal)iF(bkg)
A(signal) iS F(contamination)k
A(contamination)k dTdE F -flux from neuralino
annihilation e, antiprotons, gamma cm-2
s-1 sr-1 A -acceptance cm2 sr
RejectionA(signal)/A(contamination)
MC simulation to evaluate detector response
resolutions and acceptances Acceptances
depends on selection criteria.
Angular ECAL mode and Tracker conversion modes
Resolutions
Energy(ECAL)
Rigidity(Tracker)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 detector performance
Acceptances
Antiprotons A(lt16 GeV) 1200cm2sr
gt16GeV 330 cm2 Rejection e- 10
4 p 10 6
Preliminary
Positrons Acceptance 550 cm2
sr Rejection e- 10 3
p 10 5
Gamma (ECAL mode) Acceptance 600
cm2 sr Rejection e - 10 4
p 10 5
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential
Fixing propagation model and solar modulation .
AMS02 MC simulations.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential
Signals from neutralino annihilation
Fit signals from all components (e, gamma, p -
) simultaneously free parameters boost factors
for each component and local density r o
Positrons Normalized e fluxes from
neutralino annihilation and AMS02 MC for 1 year
of operation. Fit is done with existing data
HEAT (E lt30 GeV) NFW(1.5,2,1) halo profile ro
from fit 0.6 GeV/cm3 Corrected data points with
contamination subtracted. Signals from two CMSSM
settings m0500 m1/2350 m c137.4GeV m01000
m1/2500 m c 296GeV
S/v B (10GeV) 60
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential
Antiproton flux from c annihilation and AMS02
projection for 1Y. Fit is done with BESS data
Gamma flux from c annihilation and AMS02
projections for 1Y. Fit is done with EGRET data
Elt20GeV Integrated in 0.5ltllt30, 330ltllt359
-5ltblt5
F 550 MV
S/v B (10GeV) 20
S/v B (10GeV) 40
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential
Other experiments
Direct DM search by nuclear interactions. Discov
ery limits for existing and projected
experiments (2005-2010)
Accelerator experiments LHC (2007) will access
most of SUSY parameter space.
5s discovery contour for CMS at 100fb-1
different final states 1l -1lepton, 2lSS
-2leptons asme charge,, 2lOS-opposite, etc.
mSUGEA Ao0 , mgt0, tanb35
Spin independent search.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential
Antimatter search
Zgt2 nuclear background Hesecondary /He lt 10
-12 AMS01 limit 10 -6, AMS02 expected limit
10 -9
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential
Gamma ray astrophysics

• Diffuse gamma spectrum up to 1 TeV.

• Detailed study of gamma spectrum.
• Extra Galactic F E-2.7
• and galactic component F E-2.1
• Probe the model of gamma rays production and
  propagation.
• Study gamma rays profile vs galactic
• latitude and longitude.
• For gamma from neutralino annihilation
• the profile reflects the DM halo profile.
• Monochromatic line from neutralino
• annihilation cc-gtgg ,Zg at Em c

Experimental data , models and AMS02 projection
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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AMS02 discovery potential

• Point sources Active Galactic Centers(AGN),
  pulsars etc.

EGRET(1991) third source Catalog
AMS02 angular resolution lt2.5o ECAL mode
Egt10GeV (EGRET 2-3o) lt 0.1o Tracker conversion
E gt10GeV Acceptances A(f0) 1750 cm2 ECAL
(EGRET 1500cm2) 450 cm2 Tracker
conversion

• Source identification at Egt20GeV
• Energy spectra

Point like sources observed by EGRET at
Elt30GeV 271 sources gt100MeV

• Time variable point sources Gamma Ray
  Bursts(GRB), blazars

AMS02 can see 15 GRB/year (gt1GeV) typical GRB
in 100 sec 100 g at AMS02
Disadvantage AMS02 is attached to ISS Can't
steer the sources.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Summary
There is evidence of the supersymmetric Dark
Matter in experimental data Elt50 GeV. AMS02
will thoroughly study the range up to 200 GeV
for gamma, positron and antiproton component.
The MSSM model can be significantly constrained.
The DM halo profile structure can be verified.
AMS02 will bring down to 10-9 limit for
antimatter search proving or rejecting
baryogenesis models.
AMS02 will measure galactic and
extragalactic gamma rays up to 1 TeV range. The
gamma sources and gamma burst can be studied at
high energies.
AMS02 will measure composition of cosmic rays
and allow to tune propagation model.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003