Photoproduction of Vector Mesons and Other Resonances at 4.3 BeV

Abstract

The Stanford Linear Accelerator Center 40-in. hydrogen bubble chamber was exposed to 4.3-BeV positron-annihilation radiation. Results are presented on reactions containing no neutrals and one neutral particle in the final state. For $\gamma p\to {\rho }^{0}p$ and ${\omega }^{0}p$ we find cross sections of 19.2 ± 1.2 and 2.8 ± 0.5 μb, respectively. Assuming vector dominance, we determine the $V^{0}p$ cross sections. Evidence for other resonant states is presented, in particular ${\Delta }^{++}{V}^0{\pi }^{-}$, where we find $\frac{{\Delta }^{++}{\rho }^0{\pi }^{-}}{{\Delta }^{++}{\omega }^0{\pi }^{-}}$ about 1.5.