Observation of the GZK Cutoff by the HiRes Experiment

2006/09/14 by G. B. Thomson, Thomson, G. B.
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph

paper · pdf · doi:10.48550/arxiv.astro-ph/0609403

15 pages, 5 figures, submitted to Proceedings of the Quarks'06 Conference

arxiv created 2006/09/14 · arxiv updated 2019/08/15

Abstract

The High Resolution Fly's Eye (HiRes) experiment has observed the GZK cutoff. HiRes' measurement of the flux of cosmic rays shows a sharp suppression at an energy of 6 x 10¹⁹ eV, exactly the expected cutoff energy. We observe the ``ankle'' of the cosmic ray spectrum as well, at an energy of 4 x 10¹⁸ eV. We describe the experiment, data collection, analysis, and estimate the systematic uncertainties. The results are presented and the calculation of a five standard deviation observation of the GZK cutoff is described.

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