"The Asymmetry Between Matter and Anti Matter - or -How to Know if it is Safe to Shake an Alien's Hand?"Klaus Hon , Ohio State University [Host: Brad Cox]
ABSTRACT:
Most of us have looked at the spectacular pictures taken by the Hubble Space Telescope. Galaxies, nebulae, super novae -- but there is something peculiar about these images. Where ever we look in space we only see matter. No significant quantities of anti-matter have been found. Since we believe equal amounts of matter and anti-matter have been produced originally we must conclude that there is an asymmetry between particle and anti-particle decays. In the laboratory, however, nature always seems to obey the particle - antiparticle symmetry with one known exception. Almost 40 years ago a small difference has been found in the neutral kaon system. But the nature of this system made it extremely difficult for
both theorists and experimentalists to extract a clear picture of this effect. For years there has been great hope in the particle physics community
that a large matter - antimatter asymmetry can be observed in a new system - the weak decays of massive B mesons. The past decade has seen a vigorous experimental effort to produce the large
quantities of B mesons required to discover the cause of this asymmetry. Particle accelerators have been upgraded and new detectors were
constructed. As we enter the Golden Age of B physics nearly a billion B meson decays have been recorded by these experiments. I will review some
of the old questions that have been answered and discuss some of the new puzzles that have been uncovered.
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Colloquium Friday, April 22, 2005 4:00 PM Physics Building, Room 204 Note special time. Note special room. |
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