Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NRQCD analysis of charmonium production with pion and proton beams at
  fixed-target energies   We present an analysis of hadroproduction of $J/\psi$ and $\psi(2S)$ at
fixed-target energies in the framework of non-relativistic QCD (NRQCD). Using
both pion- and proton-induced data, a new determination of the color-octet
long-distance matrix elements (LDMEs) is obtained. Compared with previous
results, the contributions from the $q \bar{q}$ and color-octet processes are
significantly enhanced, especially at lower energies. A good agreement between
the pion-induced $J/\psi$ production data and NRQCD calculations using the
newly obtained LDMEs is achieved. We find that the pion-induced charmonium
production data are sensitive to the gluon density of pions, and favor pion
PDFs with relatively large gluon contents at large $x$.

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The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph