Search for Cosmic Antiparticles

1
Search for Cosmic Antiparticles

• First Workshop on Underground experiments and
  Astroparticle physics
• October 23, 2002
• Eun-Suk Seo
• University of Maryland Ewha Womens University

2
Discovery of Cosmic rays
3
(No Transcript)
4
BESS Spectrometer
Antiproton and proton deflect oppositely in
magnetic field
Velocity-1
Momentum

• Thin Superconducting Solenoid enables
• Cylindrical Detector ? Large Acceptance
• Uniform magnetic field? Clear separation and High
  Resolution

5
Searching for Antimatter

• Unlike antiprotons, anti-helium
• cannot be produced by collisions in the
  interstellar gas above the
• level 10-13 or so
• These 90 confidence limits on the ratio of
  anti-helium/helium in cosmic rays have been going
  down over the years
• They are now below10-6 and will be pushed to 10-7
  by longer BESS flights
• AMS-02 is expected to reach below 10-9

6
If the Universe began with a Big BangHalf of
the Universe is made out of matter
Half is made out of antimatter
Where is the Antimatter Universe?
7
(No Transcript)
8
Theories predicting the Existence of Antimatter

• The breakdown of the Time-Reversal symmetry in
  the early universe might have set different signs
  for the production of matter and antimatter in
  different regions of space
• Since there are 108 clusters of galaxies and the
  observational constraints are limited to the
  scale of the clusters, the universe can be
  symmetric on a larger scale
• The observed matter-antimatter asymmetry is
• then a local phenomenon

9

• The detection of one antihelium or anticarbon
  would have a profound impact on our understanding
  of the origin of symmetry in Time, which is the
  foundation of modern physics

10
90 of Universe is not observable

• It is made of Dark Matter

What is Dark Matter?
11
Dark Matter

• Most physicists believe that Weakly Interacting
  Massive Particle (WIMPS) comprise dark matter.
• This can be tested by direct search for various
  annihilating products of WIMPs in the Galactic
  halo

12
Detectors
13
Antiprotons from Neutralino Annihilation?
14
What do antiprotons tell us?
15
Cosmic Ray Solar Modulation
16
Randy Jokipii Views the Heliosphere .
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
A smoking gun?
Positrons from annihilating dark matter
neutralinos.
Secondary positrons produced from cosmic ray
interactions with ISM
22
Alpha Magnet Spectrometer
AMS Mounted on Full-truss Payload Site
AMS-02 Instrument Configuration.
23
(No Transcript)
24
Antiproton Measurement in 1993 - 2000 (by BESS
KEK, NASA/GSFC, Tokyo, Kobe, Maryland, and ISAS)
Northern-Canada Ballooning beyond Space Station
Orbits
Aerogel Cherenkov Counter installed
First Flight
Antiproton Observation, Year-by-Year and
Accumulated
25
Future Magnet Spectrometers
BESS
26
TIGER a record setting 31 day flight
Launch on 12/21/01
Trans-Iron Galactic Element Recorder (TIGER) is
to measure the abundance in the GCRs of each
element from sulfur (atomic number, Z16) through
zirconium (Z40).
27
Long Duration Balloon Flights in Northern
Hemisphere
28
(No Transcript)
29
Magnet Spectrometers