Speaker: Dr. Brian Mercurio, The Ohio State University
Abstract: Cosmic rays with energy greater than about 1020 eV are
expected to lose energy through interactions with the cosmic microwave background in what is known as the GZK process. Although the GZK process makes the universe opaque to the highest energy cosmic rays, it also results in the production of neutrinos that can travel nearly unattenuated from even the farthest galaxies. Because neutrinos have no electric
charge, their direction of travel is not affected by intergalactic
magnetic fields and they can point back to their sources. The Antarctic Impulsive Transient Antenna (ANITA) experiment is designed to detect GZK neutrinos with energy greater than 1018 eV. Antennas hanging from a balloon 35 km over Antarctica search for radio signals from neutrino-induced particle showers in the ice. ANITA did not discover neutrinos in this energy range, and it set a new upper limit on the neutrino flux above 1019 eV. The 2006-2007 flight also detected 16 signals that were consistent with radio emission from air
showers above the ice.