Upper limit on the ultra-high-energy photon flux from AGASA and Yakutsk data
We present the interpretation of the muon and scintillation signals of ultra-high-energy air showers observed by AGASA and Yakutsk extensive air shower array experiments. We consider case-by-case ten highest energy events with known muon content and conclude that at the 95% confidence level (C.L.) n...
Main Authors: | , , , , , , , , , , |
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Format: | Text |
Language: | unknown |
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arXiv
2006
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Online Access: | https://dx.doi.org/10.48550/arxiv.astro-ph/0601449 https://arxiv.org/abs/astro-ph/0601449 |
Summary: | We present the interpretation of the muon and scintillation signals of ultra-high-energy air showers observed by AGASA and Yakutsk extensive air shower array experiments. We consider case-by-case ten highest energy events with known muon content and conclude that at the 95% confidence level (C.L.) none of them was induced by a primary photon. Taking into account statistical fluctuations and differences in the energy estimation of proton and photon primaries, we derive an upper limit of 36% at 95% C.L. on the fraction of primary photons in the cosmic-ray flux above 10^20 eV. This result disfavors the Z-burst and superheavy dark-matter solutions to the GZK-cutoff problem. : revtex, 8 pages, 4 figures |
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