Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On relative contributions of fusion and fragmentation mechanisms in
  J/psi photoproduction at high energy   We study J/psi photoproduction via the fusion and fragmentation mechanisms at
the HERA Collider within the frameworks of the collinear parton model and the
quasi-multi-Regge kinematics approach using the factorization formalism of
non-relativistic QCD at leading order in the strong-coupling constant alpha_s
and the relative velocity v of the bound quarks. It is shown that the fusion
production mechanism dominates over the fragmentation production mechanism at
the all relevant J/psi transverse momenta. The J/psi meson p_T-spectra in the
fragmentation and fusion production at the asymptotically large p_T have equal
slopes in the quasi-multi-Regge kinematics approach, oppocite the collinear
parton model.

20
The categories of this paper are: acc-phys
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The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph