Proposal to Operate and Analyze Data from the High Resolution Fly's Eye Detector (Part III)

University Of Utah, Salt Lake City UT

Investigators

Abstract

This proposal is from the University of Utah group and requests funding to continue to operate the High Resolution Fly's Eye (HiRes) Observatory, located at the U.S. Army's Dugway Proving Ground, Utah. The HiRes observatory consists of two stations separated by 12.6 km and detects ultra high energy (UHE) cosmic rays via nitrogen fluorescence in the atmosphere. The goals of the experiment are to study the spectrum, composition and anisotropy of cosmic rays with energies starting from about 1017 eV up to beyond 1020 eV. Previous experiments, including the original Fly's Eye experiment, have shown evidence that the spectrum may continue past the predicted Greisen-Zatsepin-Kuzmin (GZK) cutoff and the nature of the events above the GZK cutoff is a puzzle. The goal of the HiRes experiment is to achieve an order of magnitude greater sensitivity than the previous Fly's Eye experiment. In earlier running of HiRes, a few outstanding events have been observed above 1020 eV, but the flux of these events is in significant disagreement with the published results from the AGASA ground array. This proposal requests funds to continue running in order to resolve this and other outstanding issues of UHE cosmic rays by measuring the properties of events with energies above 1017 eV. In addition, HiRes has a vigorous educational outreach program, ASPIRE, funded by the NSF and conducted in collaboration with the Utah State Office of Education. The goal of this program is to communicate the excitement of the scientific research to the general public. The HiRes experiment is a collaborative effort between the University of Utah, the University of Adelaide, Columbia University, Rutgers University, Montana State University, the University of New Mexico, and the University of Tokyo.