Using $5.63{\mathrm{pb}}^{-1}$ of data accumulated at the $\psi (2S)$ resonance with the CLEO III and CLEO-c detectors corresponding to $3.08\times {10}^6$ $\psi (2S)$ decays, a search is performed for the decay $\psi (2S)\to {\eta }_c{\pi }^{+}{\pi }^{-}{\pi }^0$ to test a theoretical prediction based upon the assumption that the $c\overline{c}$ pair in the $\psi (2S)$ does not annihilate directly into three gluons but rather survives before annihilating. No signal is observed, and a combined upper limit from six ${\eta }_c$ decay modes is determined to be $\mathcal{B}(\psi (2S)\to {\eta }_c{\pi }^{+}{\pi }^{-}{\pi }^0)\le 1.0\times {10}^{-3}$ at 90% C.L. This upper limit is about an order of magnitude below the theoretical expectation.

• Received 13 November 2006

DOI:https://doi.org/10.1103/PhysRevD.75.011102