"K+L0_dcs09" of "$K^+\Lambda$ and $K^+\Sigma^0$ photoproduction with fine center-of-mass energy resolution"

A2 Collaboration at MAMI. Measurements of $\gamma p \to K^+ \Lambda$ and $\gamma p \to K^+ \Sigma^0$ cross-sections have been obtained with the photon tagging facility and the Crystal Ball calorimeter at MAMI-C. The measurement uses a novel $K^+$ meson identification technique in which the weak decay products are characterized using the energy and timing characteristics of the energy deposit in the calorimeter, a method that has the potential to be applied at many other facilities. The fine center-of-mass energy (W) resolution and statistical accuracy of the new data results in a significant impact on partial wave analyses aiming to better establish the excitation spectrum of the nucleon. Systematic effects from the modeling of the experimental trigger in the simulation were typically 4% near threshold for $K^+ \Lambda$ and reducing with the beam energy. For $K^+ \Sigma^0$, the uncertainty was 2–3% near threshold and only at very backward angles. Systematic errors from non-hydrogen components of the target cell, target cell length and PID efficiency were each less than 1%.