Backward-angle photoproduction of $\ddot{I}‰$ and $\hat{I}{\cdot }^{\prime }$ mesons from protons at $E_{\hat{I}}^3=1.5-3.0$ GeV

Abstract

We report the measurement of differential cross sections for $\ddot{I}‰$ and $\hat{I}{\cdot }^{\prime }$ photoproduction from protons at backward angles ($-1.0<\cos \hat{I}{˜}_{C.M}^X<-0.8$) using linearly polarized photons at $E_{\hat{I}}^3=$$1.5-3.0$ GeV. Differential cross sections for $\ddot{I}‰$ mesons are larger than the predicted $u$-channel contribution in the energy range $2.0\le \sqrt{s}\le 2.4$ GeV. The differential cross sections for $\ddot{I}‰$ and $\hat{I}{\cdot }^{\prime }$ mesons become closer to the predicted $u$-channel contribution at $\sqrt{s}>2.4$ GeV. A bump structure in the $\sqrt{s}$ dependence of the differential cross sections for $\hat{I}{\cdot }^{\prime }$ mesons was observed at $\sqrt{s}\sim$2.35 GeV.

15pages 4figures