Cascade production in the reactions gamma p --> K+ K+ (X) and gamma p --> K^+ K^+ pi- (X)

Abstract

Photoproduction of the cascade resonances has been investigated in the reactions $γp \to K^+ K^+ (X)$ and $γp \to K^+ K^+ π^- (X)$. The mass split of the $Ξ$ doublet is measured to be $5.4\pm 1.8$ MeV/c$^2$, consistent with existing measurements. The differential (total) cross sections for the $Ξ^{-}$ have been determined for photon beam energies from 2.75 to 3.85 (4.75) GeV, and are consistent with a possible production mechanism of $Y^*\to K^+Ξ^-$ through a $t$-channel process. The reaction $γp \to K^+ K^+ π^-[Ξ^0]$ has also been investigated in search of excited cascade resonances. No significant signal of excited cascade states other than the $Ξ^-(1530)$ is observed. The cross section results of the $Ξ^-(1530)$ have also been obtained for photon beam energies from 3.35 to 4.75 GeV.