Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photoproduction of events with rapidity gaps between jets at HERA   The photoproduction of dijet events, where the two jets with the highest
transverse energy are separated by a large gap in pseudorapidity, have been
studied with the ZEUS detector using an integrated luminosity of 39 pb$^{-1}$.
Rapidity-gap events are defined in terms of the energy flow between the jets,
such that the total summed transverse energy in this region is less than some
value $E_{\rm T}^{\rm CUT}$. The data show a clear excess over the predictions
of standard photoproduction models. This is interpreted as evidence for a
strongly interacting exchange of a color-singlet object. Monte Carlo models
which include such a color-singlet exchange are able to describe the data.

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The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas