The $\sigma$ pole in $J/\psi \to \omega {\pi }^{+}{\pi }^{-}$

BES Collaboration

Using a sample of 58 million $J/\psi$ events recorded in the BESII detector, the decay $J/\psi \to \omega {\pi }^{+}{\pi }^{-}$ is studied. There are conspicuous $\omega f_2(1270)$ and $b_1(1235)\pi$ signals. At lo…