Measurement of the Flux of Ultra High Energy Cosmic Rays by the Stereo Technique

TL;DR

This paper reports the measurement of ultra-high-energy cosmic ray flux using the stereoscopic air fluorescence technique, confirming previous monocular results and observing the GZK cutoff with high precision.

Contribution

It presents the first detailed cosmic ray spectrum measurement using the stereoscopic technique, demonstrating consistency with monocular results and enhancing measurement accuracy.

Findings

Confirmed the GZK cutoff in the cosmic ray spectrum

Good agreement between stereoscopic and monocular measurements

Improved precision in cosmic ray flux measurement

Abstract

The High Resolution Fly's Eye experiment has measured the flux of ultrahigh energy cosmic rays using the stereoscopic air fluorescence technique. The HiRes experiment consists of two detectors that observe cosmic ray showers via the fluorescence light they emit. HiRes data can be analyzed in monocular mode, where each detector is treated separately, or in stereoscopic mode where they are considered together. Using the monocular mode the HiRes collaboration measured the cosmic ray spectrum and made the first observation of the Greisen-Zatsepin-Kuzmin cutoff. In this paper we present the cosmic ray spectrum measured by the stereoscopic technique. Good agreement is found with the monocular spectrum in all details.