Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $J/\psi$ photoproduction at HERA   We revise and update an earlier model for $J/\psi$ photoproduction based on a
dipole Pomeron exchange. We show that the H1 and ZEUS experimental data
reported recently can be well fitted by a soft Pomeron alone.

14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph