Search for a vector glueball by a scan of theJψresonance

The cross section for $e^{+}{e}^{-}\to \rho \pi$ has been measured by the BES detector at BEPC at center-of-mass energies covering a 40 MeV interval spanning the $\frac{J}{\psi }$ resonance. The data are used to search for the vector gluonium state hypothesized by Brodsky, Lepage, and Tuan as an explanation of the $\rho \pi$ puzzle in charmonium physics. The shape of the $\rho \pi$ cross section is compatible with that of the total hadronic cross section. No distortions indicating the presence of a vector glueball are seen.