Nucleon and Hyperon Resonances with the Crystal Ball

The Crystal Ball Spectrometer is being used at Brookhaven National Laboratory in a series of experiments which study all neutral final states of πp and Kp induced reactions. We report about the experimental setup and progress in obtaining new results for the radiative capture reactions πp → γn and Kp → γΛ,charge exchange πp → πn, two π production πp → ππn, and η production πp → ηn reactions. Data have also been obtained on the decays of N , ∆ , Λ , and Σ resonances. Threshold η production has been studied in detail for both πp and Kp. Sequential resonance decays have been investigated by studying the 2π production mechanism both in the fundamental interaction and in nuclei. In addition, we have used the ηs produced near threshold to make precision measurements searching in particular for rare and forbidden η decays.