The role of hyperon resonances in p(γ, K+)Λ processes

Abstract:We discuss the role of hyperon resonances in the u-channel when modeling pγ, K+Λ processes in an effective Lagrangian approach. Without the introduction of hyperon resonances, one is forced to use soft hadronic form factors with a cutoff mass which is at best two times the kaon mass. After inclusion of the hyperon resonances in the u-channel, we obtain a fair description of the data with a cutoff mass of the order of 1.8 GeV.