High-statistics measurements of differential cross sections and recoil polarizations for the reaction $\gamma p\to K^{+}{\Sigma }^0$ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.69 to 2.84 GeV, with an extensive coverage in the $K^{+}$ production angle. Independent measurements were made using the $K^{+}p{\pi }^{-}$($\gamma$) and $K^{+}p$(${\pi }^{-},\gamma$) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR, and LEPS results, while offering better statistical precision and a 300-MeV increase in $\sqrt{s}$ coverage. Above $\sqrt{s}\approx 2.5$ GeV, $t$- and $u$-channel Regge scaling behavior can be seen at forward and backward angles, respectively. Our recoil polarization ($P_{\Sigma }$) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles, we find that $P_{\Sigma }$ is of the same order of magnitude but opposite sign as $P_{\Lambda }$, in agreement with the static SU(6) quark model prediction of $P_{\Sigma }\approx -P_{\Lambda }$. This expectation is violated in some mid- and backward-angle kinematic regimes, where $P_{\Sigma }$ and $P_{\Lambda }$ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial-wave analyses being performed to search for missing baryon resonances.

• Received 2 June 2010

DOI:https://doi.org/10.1103/PhysRevC.82.025202