Observation of Thirteen New Exclusive Multibody Hadronic Decays of the $\psi (2S)$

Using data accumulated with the CLEO detector corresponding to an integrated luminosity of $\mathcal{L}=5.63{\mathrm{pb}}^{-1}$ on the peak of the $\psi (2S)$ [$3.08\times {10}^6$ $\psi (2S)$ decays] and $20.70{\mathrm{pb}}^{-1}$ at $\sqrt{s}=3.67\mathrm{GeV}$, we report first measurements of the branching fractions for the following 13 decay modes of the $\psi (2S)$: $\eta 3\pi$, ${\eta }^{\prime }3\pi$, $\rho K^{+}{K}^{-}$, $K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}{\pi }^0$, $2(K^{+}{K}^{-})$, $2(K^{+}{K}^{-}){\pi }^0$, $\rho p\overline{p}$, $p\overline{p}{\pi }^{+}{\pi }^{-}{\pi }^0$, $\eta p\overline{p}$, $p\overline{p}{K}^{+}{K}^{-}$, $\Lambda \overline{\Lambda }{\pi }^{+}{\pi }^{-}$, $\Lambda \overline{p}{K}^{+}$, and $\Lambda \overline{p}{K}^{+}{\pi }^{+}{\pi }^{-}$, and more precise measurements of 8 previously measured modes: $2({\pi }^{+}{\pi }^{-})$, $\rho {\pi }^{+}{\pi }^{-}$, $2({\pi }^{+}{\pi }^{-}){\pi }^0$, $\omega {\pi }^{+}{\pi }^{-}$, $K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$, $\omega K^{+}{K}^{-}$, $\varphi K^{+}{K}^{-}$, and $p\overline{p}{\pi }^{+}{\pi }^{-}$. We also report new branching fraction measurements of $\varphi {\pi }^{+}{\pi }^{-}$ and $\omega p\overline{p}$ and upper limits for $\eta {\pi }^{+}{\pi }^{-}$, $\eta K^{+}{K}^{-}$, and $\varphi p\overline{p}$. Results are compared, where possible, with the corresponding $J/\psi$ branching ratios to provide new tests of the 12% rule.

Figure 1

Distributions for the modes $2({\pi }^{+}{\pi }^{-})$ (a) and (b), $2({\pi }^{+}{\pi }^{-}){\pi }^0$ (c) and (d), and $K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ (e) and (f). The pairs of arrows indicate the signal regions. (a), (c), and (e) The scaled total energy (filled circle with error bar: $\psi (2S)$ data, solid line: Monte Carlo, shaded histogram: continuum). (b) The ${\pi }^{+}{\pi }^{-}$ invariant mass in $2({\pi }^{+}{\pi }^{-})$ (solid line: data, dashed line: like sign ${\pi }^{\pm }{\pi }^{\pm }$ invariant mass, which is used to estimate combinatorial background). (d) The ${\pi }^{+}{\pi }^{-}{\pi }^0$ invariant mass in $2({\pi }^{+}{\pi }^{-}){\pi }^0$ (filled circle with error bar: $\psi (2S)$ data, solid line: Monte Carlo, shaded histogram: continuum). (f) The $K^{+}{K}^{-}$ invariant mass in $K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$. [The symbol key is the same as (d).]