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Physical Society Colloquium
A probe of physics beyond energies > 1 EeV Prof. Eugene Loh
University of Utah A 50-joule cosmic ray landed near the Fly's Eye Detector located in Utah. This is the highest energy cosmic ray event ever recorded by mankind. Subsequently, a number of events near this energy have also been observed by the Akeno Giant Air Shower Array in Japan. Conventional theory tells us that collisions with the Cosmic Microwave Background photons should prevent these extremely energetic cosmic rays from reaching us. After describing the Fly's Eye Detector, its recent upgrades and data logged to date, I will discuss two possible explanations for how cosmic rays evade this so called GZK cutoff expected in the energy spectrum. One speculation is that they escape the cosmic microwave backgroung filter through kinematics which violate special relativity at these extreme energies. The other scenario is that they are the decay products of very energetic relics from the early universe-the so-called cosmic strings. Note: The colloquium is designed to be comprehensible to Physics junior and senior undergraduates and most graduates, research staff and faculty. Refreshments will be served in the lounge after the colloquium at 4:30. Meet the speaker informally and present your favourite questions and, maybe, speculations about the physics.
Friday, November 20th 1998, 15:30 |