Using a sample of $158\times {10}^6$ ${\rm Y}(2S)$ events collected with the Belle detector, charmonium and charmoniumlike states with even charge parity are searched for in ${\rm Y}(2S)$ radiative decays. No significant ${\chi }_{cJ}$ or ${\eta }_c$ signal is observed, and the following upper limits at 90% confidence level (C. L.) are obtained: $\mathcal{B}({\rm Y}(2S)\to \gamma {\chi }_{c0})<1.0\times {10}^{-4}$, $\mathcal{B}({\rm Y}(2S)\to \gamma {\chi }_{c1})<3.6\times {10}^{-6}$, $\mathcal{B}({\rm Y}(2S)\to \gamma {\chi }_{c2})<1.5\times {10}^{-5}$, and $\mathcal{B}({\rm Y}(2S)\to \gamma {\eta }_c)<2.7\times {10}^{-5}$. No significant signal of any charmoniumlike state is observed, and we obtain the limits $\mathcal{B}({\rm Y}(2S)\to \gamma X(3872))\times \mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}J/\psi )<0.8\times {10}^{-6}$, $\mathcal{B}({\rm Y}(2S)\to \gamma X(3872))\times \mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}{\pi }^{0}J/\psi )<2.4\times {10}^{-6}$, $\mathcal{B}({\rm Y}(2S)\to \gamma X(3915))\times \mathcal{B}(X(3915)\to \omega J/\psi )<2.8\times {10}^{-6}$, $\mathcal{B}({\rm Y}(2S)\to \gamma Y(4140))\times \mathcal{B}(Y(4140)\to \varphi J/\psi ))<1.2\times {10}^{-6}$, and $\mathcal{B}({\rm Y}(2S)\to \gamma X(4350))\times \mathcal{B}(X(4350)\to \varphi J/\psi ))<1.3\times {10}^{-6}$ at 90% C. L.

• Received 23 August 2011

DOI:https://doi.org/10.1103/PhysRevD.84.071107