Kaon photoproduction at SAPHIR for photon energies up to 2.6 GeV Original Research Article

The measurement of photoproduction reactions with open strangeness is one of the central issues of the physics program at SAPHIR. We report here on the analysis of the reactions γp→K+Σ0 and γp→K0Σ+ in the photon energy range between threshold and 2.6 GeV using data taken in the years 1997–1998. The measured cross sections suggest contributions from resonance production for both reactions. Coupled channel analysis of the two mentioned isospin channels together with the reaction γp→K+Λ also measured by SAPHIR, should help to extract resonance informations in these reactions. Upcoming data from different experiments on the photoproduction of kaon–hyperon pairs on the neutron and electroproduction of strangeness, including cross sections and polarization observables, will even improve this situation. However, for an initial discussion of what one could learn from strangeness production in the future final data for the reaction γp→K+Σ0 the preliminary SAPHIR results for the reaction γp→K0Σ+ are compared here with an isobar model designed for the previous SAPHIR data. The latter had less energy and a smaller kaon production angle resolution than new SAPHIR data and delivered data for γp→K+Λ and γp→K+Σ0 only up to 2.0 GeV and for γp→K0Σ+ up to 1.55 GeV. The new data show clearly that such a model must be refined to describe the new SAPHIR data, because these data are more sensitive to background and resonance contributions.