Searching for the origin of ultrahigh energy cosmic rays with the High Resolution Fly's Eye Stereo Detector

The High Resolution Fly's Eye (HiRes) experiment in Utah is an air fluorescence telescope mapping the sky in cosmic rays at energies above 1018 eV. Since November 1999, HiRes has been operated in stereo mode to provide cosmic ray data of unprecedented quality of the northern sky. This paper focuses on recent results from the stereoscopic data. We present a measurement of the primary chemical composition above 1018 eV, results on the search for small-scale anisotropies in the cosmic ray arrival distribution, and results on a search for point sources in the combined AGASA and HiRes stereo data set above 4.0×1019 eV.