Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hadronic Spectrum - Multiquark States   Many newly discovered mesons behave like $\ccbar$ charmonium states in that
they preferentially decay into final states that contain a $c$- and a
$\bar{c}$-quark, but do not fit expectations for any of the unfilled levels of
the conventional $\ccbar$ spectrum. There is a growing suspicion that at least
some of these states are {\it exotic}, {\it i.e.} have a substructure that is
more complex than the quark-antiquark mesons of the classical constituent quark
model. Some of these candidate states have a non-zero electric charge and,
thus, a minimal quark content of $\ccbar u\bar{d}$ or $\ccbar d\bar{u}$. In
addition, states with similar properties have been observed in the $b$- and
$s$-quark sectors. In this report, the experimental situation is briefly
reviewed.

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The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
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The categories of this paper are: cs
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
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The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
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The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph