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 $J/ψ, ψ' \to ρπ$ puzzle suggest $m_O\simeq m_{J/ψ}$, with mixing angle $\sim 2^\circ - 4^\circ$, hence $Γ(O\to ρπ$, $K^+K^-$, $e^+e^-) \sim$ MeV, few keV, few eV. Lower and upper bounds on $Γ_O$ can be argued from $e^+e^- \to ρπ$ energy scan data and the condition $B(O\to ρπ) > B(J/ψ\to ρπ)$. $O$ dominance may explain the ``large" OZI violation in $^1S_0(\bar pp)\to ϕγ$ vs. $ωγ$.