Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unmasking the ultrahigh-energy cosmic ray origin   The sharp change in slope of the ultrahigh-energy cosmic ray spectrum around
10^{9.6} GeV (the ankle), combined with evidence of a light but extragalactic
component near and below the ankle which evolves to intermediate/heavy
composition above, has proved exceedingly challenging to understand
theoretically. Recently, we introduced a very general model in which, for a
range of source conditions, photo-disintegration of ultrahigh-energy nuclei in
the region surrounding the accelerator naturally accounts for the observed
spectrum and composition of the entire extragalactic component, which dominates
above about 10^{8.5} GeV. In this communication we review the generalities of
the model and show that starburst galaxies provide a compelling source example.

15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph