Amplitude analysis of charmonium decays at CLEO-c.

We perform amplitude analyses of the decays χc1→ηπ+π- and χc1→η′π+π-, where the χc1 is produced in the radiative process ψ(2S)→γχc1. Using a data sample of 2.59×107 ψ7 decays collected by the CLEO-c detector, we find evidence for an exotic, JPC = 1-+, η′π amplitude. When interpreted as a resonance, this amplitude has parameters consistent with the π1 (1600) state quoted elsewhere. In addition, we make the first direct observation of the decay a0(980) → η′π and also compare the spectra of ππ pairs recoiling against the η and η′. [ABSTRACT FROM AUTHOR]