Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light scalar mesons in $J / psi ->$NN$meson meson$ decays in a chiral
  unitary approach   We study the four-body decays $J/\psi\to N {\bar N}$ {\it meson meson} using
a chiral unitary approach to account for the meson meson final state
interaction (FSI). The calculation of the $J/\psi\to N \bar N \pi^+ \pi^-$
process properly reproduces the experimental data after taking the FSI of
mesons and the contribution of intermediate $\rho$ meson into account. The
isoscalar resonances $\sigma$, $f_0(980)$ and the isovector resonance
$a_0(980)$ are generated through the FSI of the mesons in the channels
$J/\psi\to N \bar N \pi^0 \pi^0$ and $J/\psi\to N \bar N \pi^0 \eta$,
respectively. We also calculate the two mesons invariant mass distribution and
the partial decay width of $J/\psi\to N \bar N K^+ K^-$ and $J/\psi\to N \bar N
K^0 {\bar K}^0$, on which there is still no experimental data available.

33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio