The photoproduction of $K^{+}$ mesons and hyperons with strangeness $S=-1\mathrm{}$, in reactions of the type $\gamma +p\to Y^{*}+K^{+}$, has been studied in the $Y^{*}$ mass range 1800-2600 MeV with a missing-mass spectrometer by analyzing the structures in the $K^{+}$ yield as a function of the end point bremsstrahlung energy. The $K^{+}$ yield was observed at the laboratory angle of ${\theta }_K=10\mathrm{}°$ and at the $K^{+}$ momenta of 2.5 and 2.0 BeV/c. A fit to the $K^{+}$ yield curve suggests, in addition to a smooth background, resonancelike structure at 1820±20, 2025±20, 2250±20, and 2530±25 MeV. Widths and photoproduction cross sections for these states were measured.

• Received 9 January 1970

DOI:https://doi.org/10.1103/PhysRevD.2.1846