Astroparticle Physics with AMS02

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Astroparticle Physics with AMS-02

• Dr. C.Sbarra
• INFN-Bologna, Italy
• On behalf of the AMS collaboration
• 12th Lomonosov Conference, Moscow 2005

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Outlook

• The AMS experiment and its forthcoming operation
  on International Space Station (ISS)
• The antimatter discovery potential of AMS-02 and
  the Baryogenesis scenarios investigated
• The e , p , d detection and subsequent impact on
  the various models of exotic physics

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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The Test Experiment AMS-01
Onboard the shuttle Discovery (1998)

• Results
• Environmental studies
• Background studies
• Fulfill the constraints from space
• Antimatter/matter limit
• (lt1.1x10-6 at 95 C.L. PR 366/6, 2002)

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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The AMS-02 experiment
The Anti Matter Spectrometer

• The knowledge obtained in the precursor 10 days
  flight AMS-01 (1998) was used to redesign the
  spectrometer for the ISS
• Long exposure gt 3 years
• Superconducting magnet (BL2 0.86 T, ?1m3 fill
  volume)
• Large acceptance 0.5 m2 sr
• Many repeated measurements of particle velocity,
  momentum and charge

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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The AMS-02 experiment
PID The subdetectors

• Huge statistics of all type of Cosmic rays in the
  energy range 1 GeV 1 TeV (/nucl)
• For low rates high redundancy and precise
  detector measurements

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The AMS-02 experiment
PID The subdetectors

• 20 layers of TRD for e/h sep. (1.5 -300 GeV)
• 4 layers of TOF for trigger, time (150 ps), ß and
  Q meas.
• 8 layers of double sided Silicon tracker for p
  (10/30 µm res. b./non b.) and Q meas.
• VETO Counters
• RICH for ß (?ß/ß0.1) and Q
• 3D sampling ECAL (17X0of plastic fibers) for
  ee-/h sep. (1.5 GeV-500GeV)

Super conducting Solenoid (0.86 T)
He vessels
Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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The AMS-02 experiment
Spectrometer Resolution (P.R. 366/6)
Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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The AMS discovery potential
Antimatter in our universe

• The physical laws at microscopic level are
  symmetric between baryons and anti-baryons
• The physical Universe seems to be asymmetric
  (there seems to be only matter)
• - How can evolve an asymmetric universe (totally
  or even only locally) from a primordial big-bang
  and with symmetric laws? baryogenesis ?

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Baryogenesis

• Andrei Shakarov put the necessary conditions for
  baryogenesis JETP Lett. 91B,24 (1967)
• Baryon number B non conservation
• C and CP non conservation
• Out of equilibrium decay
• - The inflation is a natural scenario where a
  baryogenesis can take place it allows the out of
  equilibrium condition and it can avoid the
  a-prori hypothesis of initial symmetric
  conditions L.F. Abbott et Al.,Physics
  Lett.117B(1982)

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Baryogenesis

• Is the Universe globally or only locally
  asymmetric?
• In a totally symmetric universe, high energy CRs
  could escape from an antimatter domain and get to
  our galaxy
• On the basis of ?-rays observations our matter
  dominated region has at least the size of cluster
  of galaxies
• Is there place for antimatter in a totally
  asymmetric Universe as seem to be ours?

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Baryogenesis

• M. Y. Khlopov, S.G.Rubin and Al.S.Sakharov
  hep-ph/0210012
• In the matter dominated universe there is also
  the possibility of small insertions of antimatter
  regions
• Quantum fluctuations of a complex, baryonic
  charged scalar field caused by inflation can
  generate antimatter regions that can survive
  annihilation
• There can exist antistar global clusters in our
  galaxy
• The expected signature of such scenario is a flux
  of 3He and 4He accessible to AMS-02

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Experimental searches

• An anti-nucleus can be found in Cosmic Rays, with
  a spectrometer on top of the atmosphere
  (balloons) or on a satellite (Pamela, AMS-02)

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antinuclei,
antiparticles

• The antiparticles are secondaries produced by
  CR interactions with ISM through inelastic
  collisions spallation
• Flux 4He O(10-12), D O(10-8), p O(10-4), e
  O(10-3)
• But some antiparticles can be primaries from
  exotic sources of antimatter or DM annihilation
• (an He would be evidence of antistars)

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe antiparticles -
Positrons
Edsjö et al

• Ratio e/(ee-) can reveal neutralino
  annihilations
• Phys.Rev.D 65/6
• HEAT data show possible excess around 10GeV

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe antiparticles -
Positrons

• AMS can measure ?106 positrons up to 300 GeV and
  can confirm or not the bump
• Flux ratio p/e 103
• Strong p/e rejection
• - TRD Rej103/102 in 3-300 GeV
• - ECAL Rej104 for E500 GeV
• (TRD ECAL together Rej 105)

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antideuterons

• Antideuteron is to be observed in CRs
• D limit from Bess lt 1.9x10-4 (m2 ssrGeV/n)
  28th ICRC 2003
• The neutralino (the lightest supersymmetric
  particle) would be left as relic by large amount
  of sparticles decayed
• AMS-02 can observe O(10) low momentum D from
  neutralino annihilation F.Donato et Al.1999

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antideuterons

• The known ratio of D/p is 10-5 in the observed
  universe
• AMS-02 can detect D from antimatter domains D/p
  10-5 (AMS-01 observed 100 p, thus D was
  unobservable)
• The ratio of primordial He to D is 104 and in
  CR it is about 10 thus any D from antimatter
  domain would be accompaigned by He or p

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons

• Antiproton flux O(10-4) at E1 GeV
• (e-/p 103 at E 1 GeV strong e-/p
  rejection at this energy)
• Antiprotons in CRs have been detected up to O(10
  GeV) and all seem to be compatible with secondary
  production

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons

• Simulation of three years of high statistics
  measurements of antiproton spectrum
• AMS-02 will be able to detect antiprotons up to
  400GeV

V.Choutko,Nucl.Phys.B Proc.Suppl.113-2002
Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons

• Proton rejection good control of charge
  confusion, interaction with the detector and
  misreconstructed tracks
• Electron rejection use TOF RICH beta
  measurements at low energies, TRD and ECAL
  rejection capability at high energy

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons

• Wolfendale Stecker hypothesis 19th ICRC proc.
  p.354
• We know that the mean lifetime of a CR in the
  galaxy falls with energy as E-d with d0.7
• If antiprotons are produced and accelerated in an
  antimatter domain as the protons are in our
  galaxy
• The antiproton/proton ratio , at high energies,
  would go Ed with d 0.7 , the antiprotons
  being mainly extragalactic and the protons
  galactic

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons
data from Golden, Buffington, Bogolmolov

• Primary hypothesis
• p/p? E0.7
• From Stecker Wolfendale, 19th ICRC (La Jolla)
  1985, OG6.1-8, p354
• At energy Egt100GeV the experimental data could
  discriminate between primary and secondary
  hypothesis

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons

• Most recent data on p/p
• by Picozza and Morselli J.Phys.G
  Nucl.Part.Phys.29 (2003)
• Superimposed extragalactic hypothesis, black hole
  evaporation model, secondary production
• More data could discriminate between the various
  models for
• E gt10GeV

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons

• As other antiparticles, antiprotons at lower
  energy could reveal neutralino annihilation
• ?? WW,.. e, p, D, ?
• ( Indirect search in several channels )
• Flux of products depends on neutralino density,
  CRs propagation terms,..

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Antimatter in our universe Antiprotons
Ullio (1999)

• Antiprotons are particularly sensitive to the
  physics details of CR propagation (controlled by
  B/C ratio), particularly at low momentum

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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Conclusion

• The AMS-02 spectrometer will measure CRs fluxes
  with high precision for more than three years
• AMS-02 will be sensitive to antinuclei up to 100
  Mpc of distance
• AMS-02 can discriminate between a totally
  symmetric or an antisymmetric universe also
  through antiprotons at E gt100GeV
• AMS-02 will have the sensitivity to detect the
  products of DM annihilation in our galaxy through
  positrons, antideuterons and antiprotons at
  O(GeV) energy

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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SLIDES EXTRA
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The AMS-02 experiment
Operation in Space constraints

• Thermal range (day/night ?T1000 )
• Vibration (6.8 G RMS) and G-Forces (17 G, 9 G
  take off)
• Weight limitation (7000 kg)
• Power limitation (2000 W)
• Vacuum lt 10-10 Torr
• Radiation ionizing flux 1000 cm-2s-1
• Orbital debris and micrometeorites
• Must operate without human intervention
  (Redunduncy)

Dr.C.Sbarra, INFN-Bologna, Italy 12th
Lomonosov Conference, Moscow 2005
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p/pbar all recent Ams01
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p/pbar all recent data
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Energy resolution (from Palomares)
?(E)/E 3 for 100 GeV electrons
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The AMS-02 experiment
AMS ? 2 modes detection
Converted ? Detection of the ee- pair in the
tracker
Calorimeter Standalone trigger
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The AMS-02 experiment
Energy Resolution .
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The AMS-02 experiment
Angular Resolution (tracker)