Decay of the $\psi (3770)$ to light hadrons

We describe a search for $\psi (3770)$ decay to two-body non-$D\overline{D}$ final states in $e^{+}{e}^{-}$ data produced by the CESR collider and analyzed with the CLEO-c detector. Vector-pseudoscalar production ${\rho }^0{\pi }^0$, ${\rho }^{+}{\pi }^{-}$, $\omega {\pi }^0$, $\varphi {\pi }^0$, $\rho \eta$, $\omega \eta$, $\varphi \eta$, $\rho {\eta }^{\prime }$, $\omega {\eta }^{\prime }$, $\varphi {\eta }^{\prime }$, $K^{*0}\overline{K^0}$, and $K^{*+}{K}^{-}$ is studied along with that of $b_1\pi$ ($b_1^0{\pi }^0$ and $b_1^{+}{\pi }^{-}$) and ${\pi }^{+}{\pi }^{-}{\pi }^0$. The largest amount of disagreement between the expected rate for $e^{+}{e}^{-}\to {\gamma }^{*}\to X$ and that for $e^{+}{e}^{-}\to X$ at $\sqrt{s}=3.773\mathrm{GeV}$ is found for $X=\varphi \eta$, at an excess cross section of $(2.4\pm 0.6)\mathrm{pb}$ [${\Gamma }_{\varphi \eta }^{\psi (3770)}=(7.4\pm 1.6)\mathrm{keV}$], and a suggestive suppression is seen for ${\pi }^{+}{\pi }^{-}{\pi }^0$ and $\rho \pi$. We conclude with form factor determinations for $\omega {\pi }^0$, $\rho \eta$, and $\rho {\eta }^{\prime }$.

Figure 1

Scaled visible energy $E_{\mathrm{vis}}/\sqrt{s}$ for selected final states. Circles: data at $\sqrt{s}=3.773\mathrm{GeV}$, shaded histogram: data at $\sqrt{s}=3.671\mathrm{GeV}$ scaled by luminosity, dashed histogram: signal MC, arbitrary normalization. Arrows indicate selection intervals.

Figure 2

Reconstructed invariant mass distributions for selected final states. Symbols as in Fig. 1. The figures on the left (right) side pertain to the first (second) of the two final state particles.

Figure 3

Mass distributions for selected final states, continued. Symbols as in Fig. 1.

Figure 4

Dipion invariant mass distributions for the ${\pi }^{+}{\pi }^{-}{\pi }^0$ final state in data (a) at $\sqrt{s}=3.773\mathrm{GeV}$, (b) at $\sqrt{s}=3.671\mathrm{GeV}$. (c) The invariant mass of all pion pairs per event and (d) the reconstructed ${\pi }^0$ mass, in data at $\sqrt{s}=3.773\mathrm{GeV}$ (circles), data at $\sqrt{s}=3.671\mathrm{GeV}$, scaled by luminosity (shaded histogram), and phase space MC (dashed line).