First observation of $\psi (2S)\to p\bar{n}{\pi }^{-}+c.c.$

M. Ablikim, BES Collaboration

Using 14 million $\psi (2S)$ events collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider, the branching fractions of $\psi (2S)$ decays to $p \bar{n} π…