Observation of the GZK Cutoff by the HiRes Experiment
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چکیده
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 6×10 eV, exactly the expected cutoff energy. We observe the “ankle” of the cosmic ray spectrum as well, at an energy of 4× 10 eV. However we cannot claim to observe the third spectral feature of the ultrahigh energy cosmic ray regime, the “second knee”. 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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تاریخ انتشار 2006