Measurement of exclusive $��(1S)$ and $��(2S)$ decays into Vector-Pseudoscalar final states

Using samples of 102 million $��(1S)$ and 158 million $��(2S)$ events collected with the Belle detector, we study exclusive hadronic decays of these two bottomonium resonances to $\ks K^+ ��^-$ and charge-conjugate (c.c.) states, $��^+ ��^- ��^0 ��^0$, and $��^+ ��^- ��^0$, and to the two-body Vector-Pseudoscalar ($K^{\ast}(892)^0\bar{K}^0+ {\rm c.c.}$, $K^{\ast}(892)^-K^+ + {\rm c.c.}$, $����^0$, and $����$) final states. For the first time, signals are observed in the modes $��(1S) \to \ks K^+ ��^- + {\rm c.c.}$, $��^+ ��^- ��^0 ��^0$, and $��(2S) \to ��^+ ��^- ��^0 ��^0$, and evidence is found for the modes $��(1S)\to ��^+ ��^- ��^0$, $K^{\ast}(892)^0 \bar{K}^0+ {\rm c.c.}$, and $��(2S) \to \ks K^+ ��^- + {\rm c.c.}$ Branching fractions are measured for all the processes, while 90% confidence level upper limits on the branching fractions are also set for the modes with a statistical significance of less than $3��$. The ratios of the branching fractions of $��(2S)$ and $��(1S)$ decays into the same final state are used to test a perturbative QCD prediction for OZI-suppressed bottomonium decays.

8 pages, 3 figures, 2 tables, accepted for publication as a Rapid Communication in Physical Review D