Using samples of $102\times {10}^6$ ${\rm Y}(1S)$ and $158\times {10}^6$ ${\rm Y}(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to the three-body final states $\varphi K^{+}{K}^{-}$, $\omega {\pi }^{+}{\pi }^{-}$ and $K^{*0}(892)K^{-}{\pi }^{+}$, and to the two-body Vector-Tensor states ($\varphi f_2^{\prime }(1525)$, $\omega f_2(1270)$, $\rho a_2(1320)$ and $K^{*0}(892){\overline{K}}_2^{*0}(1430)$) and Axial-vector-Pseudoscalar ($K_1(1270{)}^{+}{K}^{-}$, $K_1(1400{)}^{+}{K}^{-}$ and $b_1(1235{)}^{+}{\pi }^{-}$) states. Signals are observed for the first time in the ${\rm Y}(1S)\to \varphi K^{+}{K}^{-}$, $\omega {\pi }^{+}{\pi }^{-}$, $K^{*0}{K}^{-}{\pi }^{+}$, $K^{*0}{K}_2^{*0}$ and ${\rm Y}(2S)\to \varphi K^{+}{K}^{-}$, $K^{*0}{K}^{-}{\pi }^{+}$ decay modes. Branching fractions are determined for all the processes, while 90% confidence level upper limits are established on the branching fractions for the modes with a statistical significance less than $3\sigma$. The ratios of the branching fractions of ${\rm Y}(2S)$ and ${\rm Y}(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI-suppressed bottomonium decays.

• Received 6 May 2012

DOI:https://doi.org/10.1103/PhysRevD.86.031102