Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: QED radiative correction to spin-density matrix elements in exclusive
  vector meson production   QED radiative effects are considered in the case of measurement of
spin-density matrix elements of diffractive $\rho$-meson electroproduction.
Large radiative correction for $r^5_{00}$ is found in the kinematics of
collider experiments at HERA.

25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an