Observation of the Decayψ→γρ0ρ0

Abstract

The prompt photon decay $\psi \mathrm{}\left(3095\right)\mathrm{}\to \gamma {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ has been studied with the Mark II detector at SPEAR. This channel is found to contain a $\gamma {\rho }^0{\rho }^0$ component with ${\rho }^0{\rho }^0$ masses concentrated between 1.4 and 2.0 GeV/${\mathit{c}}^2$. The branching fraction for the $\psi \to \gamma {\rho }^0{\rho }^0$ decay with masses less than 2.0 GeV/${\mathit{c}}^2$ is measured to be (1.25±0.35±0.40)×${10}^{-3\mathrm{}}$.