Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Leading order NRQCD and Light-Cone Analysis of Exclusive Charmonia
  Production in Radiative $Z$-boson Decays   The presented paper is devoted to theoretical analysis of charmonium mesons
$\eta_c$, $J/\psi$, $\chi_{c0,1,2}$, and $h_c$ production in exclusive
radiative $Z$ boson decays in the frameworks of Nonrelativistic Chromodynamic
and amplitude expansion on the light-cone. In the framework of light-cone
expansion amplitudes and widths of all processes are described with one
universal relation. It is interesting to note that from this relation it
follows automatically which component of $Z$ boson (either vector or axial)
gives contribution to the width of the particular decay. It is shown that the
effect of internal quark motion almost doubles theoretical predictions for
production of $S$-wave charmonia and $\chi_{c1}$ meson.

1
The categories of this paper are: cs
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: stat
29
The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol