Hyperon resonances in coupled channels and Crystal Ball data

Abstract

The known resonance parameters of the Λ and Σ hyperons were determined almost entirely from energy-dependent partial-wave analyses of K ¯ N scattering data. Some of these analyses attempted to obtain a consistent set of parameters for reactions involving different final states ( K ¯ N , πΛ, πΣ), but unitarity was not enforced and various features (e.g., backgrounds) were not treated consistently. Now that K − p → neutrals data are beginning to be published by the Crystal Ball Collaboration, it is timely to take a fresh look at the strangeness −1 hyperons. First results are presented for a new unitary, multichannel description of several K ¯ N reactions.