Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: eta-prime Meson Production in Nucleon-Nucleon Collisions Near The
  Threshold   The production of $\eta'$ mesons in the reactions $pp\to pp\eta'$ and $pn\to
pn\eta' $ at threshold-near energies is analyzed within a covariant effective
meson-nucleon theory. The description of cross section and angular
distributions of the available data in this kinematical region in the $pp$
channel is accomplished by including meson currents and nucleon currents with
the resonances $S_{11}(1650)$, $P_{11}(1710)$ and $P_{13}(1720)$. Predictions
for the $pn$ channel are given. The di-electron production from subsequent
$\eta'$ Dalitz decay $\eta' \to \gamma \gamma^* \to\gamma e^+e^-$ is also
calculated and numerical results are presented for intermediate energy and
kinematics of possible experiments with HADES, CLAS and KEK-PS.

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The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph