Light scalar mesons in $J/psi->$NN$mesonmeson$ decays in a chiral unitary approach

Abstract

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.

Comments: 13 pages, 5 figures in LaTex, version accepted by Phys. Rev. C