Origin of the ankle in the ultra-high energy cosmic ray spectrum and of the extragalactic protons below it [HEAP]

http://arxiv.org/abs/1505.02153


The sharp change in slope of the ultra-high energy cosmic ray (UHECR) spectrum around 10^18.6 eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle and intermediate composition above, has proved exceedingly challenging to understand theoretically. We propose a mechanism whereby photo-disintegration of ultra-high energy nuclei in the region surrounding a UHECR accelerator {\it naturally} accounts for the observed spectrum and inferred composition at Earth. Under a range of reasonable source conditions, the model reproduces the spectrum and the composition over the entire extragalactic CR range, i.e. above 10^18.6 eV. Predictions for the spectrum and flavors of neutrinos resulting from this process are also presented.

Read this paper on arXiv…

M. Unger, G. Farrar and L. Anchordoqui
Mon, 11 May 15
23/44

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