Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The structure of the light scalar mesons and QCD sum rules   The structure of the light scalar mesons is elucidated by the investigation
of the S-matrix poles and the q-qbar spectral density in a coupled channel
model that includes pi-pi, K-Kbar and q-qbar channels. It is shown that the
dynamical origin of the sigma and f0(980) mesons is consistent with the
observed spectrum of the scalar states. The K-Kbar molecular picture of the
f0(980) is in good agreement with recent experimental data on the decay phi -
gamma pi pi from Novosibirsk.

24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin