Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
Abstract:
From direct observations of the longitudinal development of ultra-high energy air showers performed with the Pierre Auger Observatory, upper limits of 3.8%, 2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray photons above 2, 3, 5 and 10 EeV (1 EeV ≡ 1018 eV), respectively. These are the first experimental limits on ultra-high energy photons at energies below 10 EeV. The results complement previous constraints on top-down models from array data and they reduce systematic uncertainties in the interpretation of shower data in terms of primary flux, nuclear composition and proton-air cross-section. © 2009 Elsevier B.V. All rights reserved.
Año de publicación:
2009
Keywords:
Fuente:


Tipo de documento:
Article
Estado:
Acceso restringido
Áreas de conocimiento:
- Física de partículas
Áreas temáticas:
- Física moderna
- Astronomía y ciencias afines
- Cuerpos y fenómenos celestes específicos
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