Glueballs: Charmonium Decay and $\bar p p$ Annihilation

Abstract

The vector glueball $O$, made of 3 valence gluons, is expected to be ``clean": it mixes less with quarkonia, but mediates OZI violations. The recent $0^{++} $ glueball candidate and the persistence of the $J/\psi, \psi' \to \rho\pi$ puzzle suggest $m_O\simeq m_{J/\psi}$, with mixing angle $\sim 2^\circ - 4^\circ$, hence $\Gamma(O\to \rho\pi$, $K^+K^-$, $e^+e^-) \sim$ MeV, few keV, few eV. Lower and upper bounds on $\Gamma_O$ can be argued from $e^+e^- \to \rho\pi$ energy scan data and the condition $B(O\to \rho\pi) > B(J/\psi\to \rho\pi)$. $O$ dominance may explain the ``large" OZI violation in $^1S_0(\bar pp)\to \phi\gamma$ vs. $\omega\gamma$.