Measurement of the Photon Beam Asymmetry Σ for γ+p->K⁺Σ⁰ at E_γ = 8.5 GeV in GlueX

We present measurements of the photon beam asymmetry Σ for the reaction γp->K⁺Σ⁰(1193) using the GlueX experiment in Jefferson Lab's Hall D. Data were collected using a linearly polarized photon beam with energy range 8.2-8.8 GeV incident on a liquid hydrogen target. Asymmetries are measured as functions of Mandelstam variables t and u. These are the first exclusive measurements of the photon beam asymmetry Σ in this reaction at high energies. In the t-channel, results show that the reaction is dominated by the natural-parity exchange of presumably the K^*(892) meson, as predicted by theoretical models. Results obtained for the u-channel are consistent with an intermediate baryon exchange mechanism predicted by theoretical models.