Pierre Auger Data, Photons, and Top-Down Cosmic Ray Models

Abstract

We consider the ultra-high energy cosmic ray (UHECR) spectrum as measured by the Pierre Auger Observatory. Top-down models for the origin of UHECRs predict an increasing photon component at energies above about $10^{19.7}$eV. Here we present a simple prescription to compare the Auger data with a prediction assuming a pure proton component or a prediction assuming a changing primary component appropriate for a top-down model. We find that the UHECR spectrum predicted in top-down models is a good fit to the Auger data. Eventually, Auger will measure a composition-independent spectrum and will be capable of either confirming or excluding the quantity of photons predicted in top-down models.

8 pages, 3 figures

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Cited by in corpus (6)

• Upper limit on the cosmic-ray photon flux above 10^19 eV using the surface detector of the Pierre Auger Observatory
• Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
• Search for ultra-high energy photons using air showers
• Improving photon-hadron discrimination based on cosmic ray surface detector data
• The Passage of Ultrarelativistic Neutralinos through Matter
• Signals of Very High Energy Neutralinos in Future Cosmic Ray Detectors