Highest Energy Cosmic Rays and results from the HiRes Experiment

Understand

The status of the field of ultrahigh energy cosmic rays is summarized, from the point of view of the latest results of the High Resolution Fly's Eye (HiRes) Experiment.

• HiRes results are presented, and compared with those of the Akeno Giant Air Shower Array (AGASA), plus the Telescope Array and Pierre Auger experiments.
• The HiRes measurements of the cosmic ray spectrum, and the observation of the GZK cutoff are presented.
• HiRes results on composition, searches for anisotropy, measurement of the proton-air total cross section, and shapes of shower profiles are presented.