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
• Detector 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 Y mission on board of ISS. The
only general purpose experiment at ISS

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• 1929 Hubble constant
• HV/R H 100h 0 km/s Mpc h 00.710.03
• ?c??????????G ?????c
  ?tot?????????Matter(1z)3
• Big Bang
• Expanding Universe dominated by Dark Energy ??

• 1963 Cosmic Microwave Background (CMB)
• T2.725 0.001K
• 2002 CMB anisotropy by WMAP
• ???tot ????????????????????DarkMatter??????ar
  yonicMatter?
• 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
• Inflation
• Dark Matter
  

WMAP CMB anisotropy
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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• Rotation curves of spiral galaxies
• v 2GM(r)/r const ?(r)3v 2/4?Gr2
• ??DMhalo? gtgt ??visible ??visible lt 0.005
• Dark Matter halo

• Abundances of elements
• Primordial nucleosynthesis
• 0.16 gt ??baryonic gt 0.015
• ??????baryons ????????????????????????(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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• 80's Standard Model (SM)
• W,Z, t, mn , 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 lightest
  particle (LSP) which weakly interacts with normal
  matter (WIMPS)
• Provides coupling constant unification
• Includes gravity symmetry breaking
• mSUGRA, MSSM , ...

• Quantum gravity
• String theory, Extra Dimensions?
• GUT

V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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DM decoupling
R e tH
Rt2/3
Rt1/2
?
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Dark Matter
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 (?annih?????at??t
??10 -10 s and can be seen now as a
relic. Nucleosynthesis starts at ?? 1 min after
BB and produces most of H and He. Baryogenesis
explains Baryon asymmetry baryon number
violationC and CP violationout of equilibrium
decay . But existence of local Antimatter
domains at dgt10 Mpc is not excluded! Structure
formation is determined by the density
fluctuations of DM after freeze out. Baryonic
matter joints the formation after decoupling
from radiation (last scattering)4 106 year after
BB
Can we see Antimatter ?
Dark Matter?
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Main parameters in MSSM A o, m1/2 , m o
, tan?, ??? LSP is a bino-like neutralino
m????????0.4 m1/2 neutralino is a spin ½
Majorana particle and can annihilate Neutralino
is the Dark Matter candidate N
1. Constrains from GUT coupling unification
and Electroweak Symmetry breaking
(EWSB) preferable solution with tan ??gt30 and
A00 m?????gt 120 GeV
Evolution of mass spectrum from Renormalization
group equation (RGE)
,
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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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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Annihilation of neutralino
??????Tree diagrams
Dominant channelgt90
after hadronization and decays p, p , e,
e- , ? are stable and can reach the Earth with
a continuum energy spectra
??? 1 loop? diagrams
...
Monochromatic gamma lines E ? m ?????m
????mz2/4m?
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Effective thermal average cross section lt ?eff
Vgt A/n2 A -annihilation rate, n-equilibrium
density Dependence on m 0 , m1/2 and tan?????
m??0.4 m ½ , ? ?? m??2 )
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Background Cosmic Ray spectra is dominant by SM
stable particles p, He, e- Have chance to see
signal from ?? annihilation in e, p and
? components where backgrounds from nuclear
interactions is smaller.

Flux for i -component is
lt ?eff Vgt and Ai are calculated in CMSSM
Halo profile ? Propagation ?
Background cosmic ray spectra
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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From rotation curves - neutralino is spherically
distributed around galactic center. Navarro,
Frenk, White type Dark Matter halo profile
????????????define the slope ??0 - local density
0.3-0.7 GeV/cm3 a -scale parameter (depends
on ?0) integrate ????r??along line of
sight l r 2 l2r02-2lr0cos ?
We are here ro 8kpc

V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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• Propagation (diffusion in interstellar media
  with magnetic field 4 ?G ,
  reacceleration, convection, spallation, etc)
• Background production (supernova, pulsars,
  black holes, etc)
• Secondary particle production (nuclear
  interactions with IS gas )
• Solar modulations

The propagation parameters can be fixed from
isotopes abundances.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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• Important parameters
• Dxx ? Do p ??????????Do??diffusion coefficient
  , defined from B/C ratio.
• size of the galactic disk Rh30kpc, zh4
  -12kpc and propagation time defined from 10Be/
  9Be
• va - Alfven speed for reacceleration models
  20-40 km/s
• Nucleur cross sections has to fit observed
  element abundances p-gtC,N,O-gtBe,B, pbar, e-
• Size of interstellar gas and density of hydrogen
  from He3/He4
• Solar modulation parameters ??????????MV

Problems in the model (Galprop)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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• Gamma propagates without (almost) interactions
  but needs to be in the detector acceptance,
  therefore smaller contribution.
• Positrons and Antiprotons diffuse long distances
  and interacts with IS gas before reaching the
  Earth. Positrons travels less due heavier losses.

Galactic center
Contributions to the annihilation signal from
different part of DM halo.
Fluxes per annihilation produced in the DM
halo (left) and after propagation(right)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Installed on International Space Station (ISS)
400km orbit from 2006 for 3 Years(without
assistance)
1998 AMS01 precursor flight on board of
Discovery STS 91 (100h ) with permanent magnet
0.15T, Tracker and ToF
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Superconductive Magnet Bdipol 0.87 Tesla
I459A Size d1.2m l0.8 m Mass 2.3
t cooled to 1.8K by superfluid He (2500 l
reservoir for 3 years)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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MC simulation to evaluate detector response
resolutions and acceptances
Resolutions
Angular ECAL mode and Tracker conversion modes
Rigidity(Tracker)
Energy(ECAL)
Number of events of i - component measured by
AMS02 is N tot i F(signal)i A(signal)iF(bkg)
A(signal) i??F(contamination)k
A(contamination)k dT dE F -flux from neuralino
annihilation e, antiprotons, gamma cm-2
s-1 sr-1 A -acceptance cm 2 sr
RejectionA(signal)/A(contamination)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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MSU , August 2003
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Acceptances defined by selection cuts during
reconstruction
Antiprotons A(lt16 GeV) ??1200cm 2sr
gt16GeV ? 330 cm 2 Rejection e- ?
10 4 p ? 10 6
Preliminary
Positrons Acceptance ? 550 cm 2
sr Rejection e- ? 10 3
p ? 10 5
Gamma (ECAL mode) Acceptance 600
cm 2 sr Rejection e - 10 4
p 10 5 Gamma (Conversion
mode) Acceptance 550 cm 2 sr

V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Antimatter search
Negative Z gt2 nuclear background
Hesecondary /He lt 10 -12 AMS01 limit 10 6,
AMS02 expected 10 -9 is limited by statistics
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Fixing propagation model , backgrounds from
nuclear interactions and solar modulation. Precis
e measurement s of chemical compositions up to
1 TeV.
AMS02 MC simulations.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Indirect Dark Matter search in AMS

• Signal from neutralino annihilation in positrons,
  antiprotons and gamma spectrums.
• Unknown parameters
• Halo profiles can be constrained from rotation
  curves.
• Signal from annihialtion can be estimated from
  MSSM.
• Propagation model can be constarined from
  chemical composition of CR.
• Boost factors (B(e),B(p-), B (?)) related to
  the possible high density clumps
• of Dark Matter (Flux r2) can be constrained
  with simultaneous fit of positron,
• antiproton and gamma spectrums.

Lets consider 1) NFW type halo profile with
a1.5 b2 g1 a2kpc ro0.6 GeV/cm3 2) MSSM
mo500 m1/2350 tanb50 which yields mc 143.7
GeV0.4 m1/2 . (Increase of mc will
drastically decrease the flux i.e. requires
large Boost factor 1/mc 4 ) 3) Boost factors
close to 1 i.e. B(antiprotons)1 B(gamma)1.1
and B(positrons)1.5 from the best fit of
experimental data ( HEAT,BESS,EGRET)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Positrons
Specific bump at 5-40 GeV GeV. Small
contamination and large significance
Significance S/v Bkg
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Gamma (ECAL mode)
Statistics is limited by the acceptance
and exposure time when AMS02 is faced to the
Galactic center.
Significance S/v Bkg
Statistics can be doubled by using gamma
reconstruction g-gtee- in the
Tracker(conversion mode)
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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??550 MV
Antiprotons
Difficult case since the shapes of the signal
and background are similar and the low energy
part(lt10GeV) is prone to solar modulation.
Significance S/v Bkg
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Other experiments
Direct DM search by nuclear interactions. Discove
ry limits for existing and projected experiments
(2005-2010)
Accelerator experiments LHC (2007) will access
most of mSUGRA parameter space.
144 GeV
5??discovery contour for CMS at 100fb-1
different final states 1l -1lepton, 2lSS
-2leptons asme charge,, 2lOS-opposite, etc.
MSUGRA Ao0 , ?gt0, tan?35
Spin independent.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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Gamma ray astrophysics powerful tool to test
the Univers

• 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.
• Gamma from neutralino annihilation
• reflects the DM halo profile.
• Monochromatic lines from neutralino
• annihilation???-gt?????????at Em ?. can
  constrain
• the clumpiness.

Experimental data , models and AMS02 projection
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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• Point sources Active Galactic Centers(AGN),
  pulsars etc.

EGRET(1991) third source Catalog
AMS02 angular resolution lt 2.5o ECAL mode
Egt10GeV lt 0.1o Tracker conversion E
gt10GeV (EGRET 2-3o GLAST 0.1o) Acceptances
A(?0) ? 1750 cm2 ECAL ?
450 cm2 Tracker conversion (EGRET
1500cm2,GLAST 12000 cm2)

• Source identification at Egt20GeV
• Energy spectra of sources

Point like sources observed by EGRET at
Elt30GeV 271 sources gt100MeV

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

Extrapolating EGRET results AMS02 can see 10
GRB/year (gt1GeV)
Disadvantage AMS02 is attached to ISS and can't
steer the sources.
V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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V. Zhukov University of Karlsruhe, IEKP
MSU , August 2003
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