Do psi(4040), psi(4160) signal Hybrid Charmonium?

Abstract

We suggest that $\psi$ (4040) and $\psi$ (4160) are strong mixtures of ground state hybrid charmonium at $\sim 4.1$ GeV and the $\psi (3S)$ of conventional charmonium. The $\Gamma^{e^+e^-}$, masses and total widths of the $\psi(4040)$ and $\psi(4160)$ are in accord with this hypothesis. Their hadronic decays are predicted to be dominated by the $\psi (3S)$ component and hence are correlated. In particular we find a spin counting relation $\Gamma (4160 \rightarrow D_sD_s^*) \sim 4 \Gamma (4040 \rightarrow D_sD_s)$ due to their common $\psi(3S)$ component. For $D$ and $D^*$ production, using $\psi(4040)$ branching ratios as input, we predict that the decay pattern of the $\psi(4160)$ will be very different from that of the $\psi(4040)$. These predictions may be tested in historical data from SPEAR, BES or at future Tau-Charm Factories.