Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The description of $F_2$ at low $Q^2$   We analyse the data for the proton structure function $F_2$ over the entire
$Q^2$ domain, including especially low $Q^2$, in terms of perturbative and
non-perturbative QCD contributions. The small distance configurations are given
by perturbative QCD, while the large distance contributions are given by the
vector dominance model and, for the higher mass $q \bar{q}$ states, by the
additive quark approach. The interference between states of different
$q\bar{q}$ mass (in the perturbative contribution) is found to play a crucial
role in obtaining an excellent description of the data throughout the whole
$Q^2$ region, including photoproduction.

26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
1
The categories of this paper are: cs
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph