Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Role of a four-quark and a glueball state in pion-pion and pion-nucleon
  scattering   We consider the two-flavor version of the extended linear sigma model (eLSM),
which contains (pseudo)scalar and (axial-)vector quark-antiquark mesons, a
scalar glueball (predominantly corresponding to $f_{0}(1710)$), as well as the
nucleon and its chiral partner. We extend this model by the additional light
scalar meson $f_{0}(500)$, predominantly a putative four-quark state. We
investigate various interaction terms of the four-quark and glueball states
with the other particles, some of which preserve and some of which explicitly
break the $U(1)_{\textrm{A}}$ symmetry. We test our model by performing a
global fit to masses and decay widths of the scalar resonances and pion-pion
scattering lengths. We also discuss the influence of the scalar four-quark
state and the glueball on the baryon sector by evaluating pion-nucleon
scattering parameters. We find that the inclusion of $f_{0}(500)$ improves the
description of pion-pion and pion-nucleon scattering lengths.

13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
18
The categories of this paper are: econ
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys