Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Eta-nucleon and eta-prime-nucleon coupling constants in QCD and the role
  of gluons   Coupling constants of $\eta$ and $\eta^{\prime}$ mesons with nucleons have
been calculated using the method of QCD sum rules. Starting from
vacuum-to-meson correlation function of interpolating fields of two nucleons,
its matrix element with respect to nucleon spinors has been considered.
Coupling constants at the physical points have been estimated from
extrapolation of results obtained at two other points. Anomalous glue has been
found to give substantial contribution to the coupling constants and also
accounts for a significant OZI-rule violation.

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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
2
The categories of this paper are: math
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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
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The categories of this paper are: acc-phys