Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coherent Photoproduction of Eta-Mesons on Spin-Zero Nuclei in a
  Relativistic, Non-local Model   The coherent photoproduction of $\eta$-mesons on spin-zero nuclei is studied
in a relativistic, non-local model, which we have previously applied to the
coherent photoproduction of pions. We find that different off-shell
extrapolations of the elementary production operator lead to large effects in
the cross section. We also show that the almost complete suppression of the
N(1535) seen in earlier studies on this reaction is a result of the local or
factorization approximation used in these works. Non-local effects can lead to
a considerable contribution from this resonance. The relative size of the
N(1535) contribution depends on the structure of the nucleus under
consideration. We give an estimate for the contribution of the N(1520)
resonance and discuss the effect of an $\eta$-nucleus optical potential

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The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
8
The categories of this paper are: hep-ex
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The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat
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The categories of this paper are: math
6
The categories of this paper are: astro-ph