Physical Society Colloquium

The cosmic ray energy spectrum extends to extraordinarily high energies, beyond 10²⁰ eV. The particles at the highest energy frontier pose a great challenge, both theoretically and experimentally. Their origin and acceleration are still a mystery. The hard experimental evidence is still weak, because event rates are so small. What experimental evidence exists, e.g. with the AGASA and HiRes experiments, is controversial and the subject of intense debate. The current situation will be reviewed, and the incipient Pierre Auger Observatory effort will be described, which aims at resolving the controversies with an array of detectors deployed over 3000 km² in Western Argentina.

Friday, January 10th 2003, 15:30
Ernest Rutherford Physics Building, Keys Auditorium (room 112)