Observation an anηc′Candidate State with Mass 3592 ±5 MeV

An ${{\eta }_c}^{\prime }$ candidate state is observed at a mass $M=3592\mathrm{}\pm 5$ MeV and with a natural linewidth $\Gamma <8\mathrm{}$ MeV (95% confidence level), by using the "crystal ball" NaI(Tl) detector at the Stanford Linear Accelerator Center (SPEAR). The evidence is found in the inclusive photon spectrum in decays of the ${\psi }^{\prime }\mathrm{}\left(3684\right)\mathrm{}$, where a signal is observed corresponding to a radiative transition to this state with branching ratio between 0.2% and 1.3% (95% confidence interval, including an uncertainty due to correlation with width).