Antimatter Past Present Future Presentation By Paramita Barai

Antimatter: Past, Present & Future Presentation By Paramita Barai In Course Phys 6410: Introductory Nuclear and Particle Physics Instructor: Dr. Xiaochun He Department of Physics and Astronomy Georgia State University May, 2003

Contents n n n n n Introduction to Antimatter Matter-Antimatter Asymmetry after Big Bang History of Antimatter till Today Antihydrogen Atom Production Uses of Antimatter Propulsion Missions to Detect Antimatter in the Universe Present Status of Antimatter Search Further Scopes

Introduction to Antimatter n n Every matter particle has antiparticle, most properties same, but few are different (charge) Mass- Energy interconversion n n Matter antimatter annihilate to form energy Always particle-antiparticle pair created from energy Our world is of matter, so should have equal amount of antimatter … Where is the antimatter gone ? We don’t see any around today !!!

Matter-Antimatter Asymmetry After Big Bang n n n At origin – continuous mass energy interconversion – particles antiparticles created annihilated Universe expanded and cooled Somehow for every million pairs one more particle created Temperature dropped, no longer particle creation, all antiparticles destroyed Remaining particles made up the stars, planets, trees, you and me … CMBR: Relic of matter antimatter battle

History of Antimatter till Today n n n 1928: Prediction of antiparticle by Paul Dirac 1930: Positron detected 1955: Antiproton and Antineutron 1965: Antideutron 1995: Production of first antihydrogen atom 2002 (16 th sept): Controlled production of large no. of antihydrogen atoms

Antihydrogen Atom Production n n n Accelerated proton - hits metal target, proton antiproton pair created from energy released Antiprotons collected in a beam by electric field, the beam controlled by bending and focusing magnets Radio frequency cavity slows down the antiprotons When c/10, antiproton bunch squeezed out to new path by magnets, and stored in traps by magnetic field Positrons collected from decay of a radioactive isotope Positrons and antiprotons in mixing trap from antihydrogen atom

Practical Uses of Antimatter n Medical frontier n PET (Positron Emission Tomography) Scan n Brain Other Parts of Body Early and effective diagnosis

Antimatter Propulsion n n Matter antimatter annihilations ultimate source of energy Speculations about antimatter fueled rockets, going to far off stars

Missions to Detect Antimatter in Universe n n Try to detect extensive regions of gamma rays coming from matter antimatter annihilations Search for galactic and extragalactic antinuclei, antiatoms – antiparticle detector in space n n Balloon experiments (IMAX) By Satellites n AMS: (ISS in 2004)

Present Status Of Antimatter Search n n No evidence of vast regions of antimatter Detected n in universe n n at isolated spots In milky way Antimatter clouds at center, origin not sure Antimatter annihilation radiation n

Further Scopes n n Study antiatom properties, and compare with that of atom Explain perceived antimatter asymmetry of universe n n In 1999, Fermilab charge parity violation discovered Detect antimatter n AMS ( Alpha magnetic Spectrometer)

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