Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The $\eta^\prime g^* g^{(*)}$ Vertex Function in Perturbative QCD and
  $\eta^\prime$-Meson Mass Effects   The $\eta^\prime g^* g^{(*)}$ effective vertex function (EVF) is calculated
in the QCD hard-scattering approach, taking into account the
$\eta^\prime$-meson mass. We work in the approximation in which only one
non-leading Gegenbauer moment in both the quark-antiquark and gluonic
light-cone distribution amplitude for the $\eta^\prime$-meson is kept. The EVF
with one off-shell gluon is shown to have the form $F_{\eta^\prime g^* g}
(q_1^2, 0, m_{\eta^\prime}^2) = m_{\eta^\prime}^2 H(q_1^2)/(q_1^2 -
m_{\eta^\prime}^2)$, valid for $|q_1^2| > m_{\eta^\prime}^2$. An interpolating
formulae for the EVF in the space-like region of the virtuality $q_1^2$, which
satisfies the QCD-anomaly normalization for on-shell gluons and the
perturbative-QCD result for the gluon virtuality $|q_1^2| \gtrsim 2 GeV^2$, is
also presented.

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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: nlin
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The categories of this paper are: cs
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: astro-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org