Observation of the GZK Cutoff Using the HiRes Detector

Abstract

The High Resolution Fly's Eye (HiRes) experiment has observed the GZK cutoff. HiRes observes two features in the ultra-high energy cosmic ray (UHECR) flux spectrum: the Ankle at an energy of $4\times 10^{18}$ eV and a high energy suppression at $6\times 10^{19}$ eV. The later feature is at exactly the right energy for the GZK cutoff according to the $E_{1/2}$ criterion. HiRes cannot claim to observe a third feature at lower energies, the Second Knee. The HiRes monocular spectra are presented, along with data demonstrating our control and understanding of systematic uncertainties affecting the energy and flux measurements.

arXiv comment8 pages, 12 figures. Proceedings submission for CRIS 2006, Catania, May/June 2006

References in corpus (6)

• The spectrum features of UHECRs below and surrounding GZK
• The Energy Spectrum of Cosmic Rays Above $3\times 10^{17}$ eV as measured with the Haverah Park Array
• Photon yields from nitrogen gas and dry air excited by electrons
• Measurement of Pressure Dependent Fluorescence Yield of Air: Calibration Factor for UHECR Detectors
• Techniques for measuring atmospheric aerosols at the High Resolution Fly's Eye experiment
• Studies of systematic uncertainties in the estimation of the monocular aperture of the HiRes experiment

Cited by in corpus (12)

• First Observation of the Greisen-Zatsepin-Kuzmin Suppression
• Cosmic Rays: The Second Knee and Beyond
• Analysis of large-scale anisotropy of ultra-high energy cosmic rays in HiRes data
• The ExaVolt Antenna: A Large-Aperture, Balloon-embedded Antenna for Ultra-high Energy Particle Detection
• Cosmic rays from active galactic nuclei
• Composition of cosmic rays accelerated in active galactic nuclei
• Ultra High-Energy Cosmic Ray Observations
• The current status of orbital experiments for UHECR studies
• Early Results from TUS, the First Orbital Detector of Extreme Energy Cosmic Rays
• Latest Results from HiRes
• The 320 EeV Fly's Eye event: a key messenger or a statistical oddity ?
• About the consistency of the energy scales of past and present instruments detecting cosmic rays above the ankle energy