Study ofγp→ρωwith Linearly Polarized Photons at 2.8 and 4.7 GeV

The reaction $\gamma p\to \rho \omega$ was studied in a hydrogen bubble chamber using a linearly polarized photon beam. The total cross section was found to be 5.8 ± 0.5 μb at 2.8 GeV and 3.2 ± 0.3 μb at 4.7 GeV. From the decay angular distributions these cross sections have been separated into contributions from natural- and unnatural-parity exchange ${\sigma }^{\mathrm{N}}$, ${\sigma }^{\mathrm{U}}$ in the $t$ channel. For $\mathrm{}\left|t\right|<1\mathrm{}$ Ge${\mathrm{V}}^2$ ${\sigma }^{\mathrm{N}}=2.5\mathrm{}\pm 0.4$ μb, ${\sigma }^{\mathrm{U}}=2.7\mathrm{}\pm 0.4$ μb at 2.8 GeV and ${\sigma }^{\mathrm{N}}=1.8\mathrm{}\pm 0.3$ μb, ${\sigma }^{\mathrm{U}}=1.3\mathrm{}\pm 0.3$ μb at 4.7 GeV. The contributions from unnatural-parity exchange are consistent with the predictions of the one-pion-exchange model.