Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hadronic Final States and Diffraction at HERA   Recent results from the ep (electron-proton) collider HERA are presented. Jet
production and diffraction type reactions allow tests of predictions of Quantum
Chromodynamics (QCD). Jet measurements are used to improve the combined H1-ZEUS
parton density fits by adding an additional constraint on the gluon
distribution in the proton and, at the same time, providing information on
strong coupling constant. Measurements of inclusive diffraction and diffractive
dijet data are discussed in the context of factorisation in diffraction.
Diffractive Upsilon(1S) production was studied to extract the t-slope of the
process, which was found to be consistent with the other exclusive vector meson
data and can be interpreted in terms of the gluonic radius of the proton.

2
The categories of this paper are: math
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs