Joint Astrophysics Colloquium

The Highest Energy Cosmic Rays and Neutrinos

Jim Beatty

Ohio State University

Cosmic rays have been observed with energies of tens of joules. At these energies particles are attenuated by interactions with the cosmic microwave background radiation, and must come from nearby. The resulting feature in the cosmic ray spectrum has been observed, and cosmic rays above this energy are anisotropic. Neutrinos produced in the interaction of cosmic rays with the microwave background can be detected by radio techniques from high altitude balloons viewing the Antarctic ice sheet. I will discuss the status of these cosmic ray observations and of efforts to detect these neutrinos.