Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exclusive vs. diffractive vector meson production in DIS at small x or
  off nuclei   The diffractive production of vector mesons in deep inelastic scattering
(DIS) is calculated in the McLerran-Venugopalan model. This is relevant when
large parton densities are probed by the virtual photon, as is the case at
small Bjorken x or in DIS off nuclei. We investigate differences between the
exclusive production (when the target doesn't break up) which dominates at
small momentum transfer squared |t|, and the diffractive production (when the
target scatters inelastically) which dominates at large |t|.

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The categories of this paper are: physics
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc