The highest energy cosmic rays: the past, the present and the future
arXiv:1901.06676 · doi:10.1051/epjconf/201921000001
Abstract
The greater part of this paper is concerned with a historical discussion of the development of the search for the origins of the highest-energy cosmic-rays together with a few remarks about future prospects. Additionally, in section 6, the situation with regard to the mass composition and energy spectrum at the highest energies is discussed. It is shown that the change of the depth of shower maximum with energy above 1 EeV, measured using the Telescope Array, is in striking agreement with similar results from the Auger Observatory. This implies that either the mean mass of cosmic rays is becoming heavier above ~4 EeV or that there is a change in details of the hadronic interactions in a manner such that protons masquerade as heavier nuclei. A long-standing controversy is thus resolved: the belief that pure protons dominate the mass distribution at the highest energies is no longer tenable.
arXiv commentTo appear in Proceeding of UHECR2018 (Paris): 16 pages and 6 diagrams
References in corpus (6)
- KASCADE measurements of energy spectra for elemental groups of cosmic rays: Results and open problems
- Indications of Intermediate-Scale Anisotropy of Cosmic Rays with Energy Greater Than 57 EeV in the Northern Sky Measured with the Surface Detector of the Telescope Array Experiment
- Depth of Maximum of Air-Shower Profiles at the Pierre Auger Observatory: Composition Implications
- Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode
- Extensive Air Showers and Ultra High-Energy Cosmic Rays: A Historical Review
- The photodisintegration of cosmic ray nuclei by solar photons: the Gerasimova-Zatsepin effect revisted