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 Women’s University

2. Discovery of Cosmic rays Eun-Suk Seo, University of Maryland

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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 andHigh Resolution Eun-Suk Seo, University of Maryland

5. Searching forAntimatter • 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 Eun-Suk Seo, University of Maryland

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? Eun-Suk Seo, University of Maryland

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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 Eun-Suk Seo, University of Maryland

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 Eun-Suk Seo, University of Maryland

10. 90% of Universe is not observable It is made of Dark Matter What is Dark Matter? Eun-Suk Seo, University of Maryland

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 WIMP’s in the Galactic halo Eun-Suk Seo, University of Maryland

12. Detectors Eun-Suk Seo, University of Maryland

13. Antiprotons from Neutralino Annihilation? Eun-Suk Seo, University of Maryland

14. What do antiprotons tell us? Eun-Suk Seo, University of Maryland

15. Cosmic Ray “Solar” Modulation Eun-Suk Seo, University of Maryland

16. Randy Jokipii Views the Heliosphere …. Eun-Suk Seo, University of Maryland

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21. A smoking gun? Positrons from annihilating dark matter neutralinos. Secondary positrons produced from cosmic ray interactions with ISM Eun-Suk Seo, University of Maryland

22. Alpha Magnet Spectrometer AMS Mounted on Full-truss Payload Site AMS-02 Instrument Configuration. Eun-Suk Seo, University of Maryland

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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 Eun-Suk Seo, University of Maryland

25. Future Magnet Spectrometers BESS Eun-Suk Seo, University of Maryland

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, Z=16) through zirconium (Z=40). Eun-Suk Seo, University of Maryland

27. Long Duration Balloon Flights in Northern Hemisphere Eun-Suk Seo, University of Maryland

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29. Magnet Spectrometers Eun-Suk Seo, University of Maryland