Faddeev Calculation of the K−d →πΣn Reaction in the Λ(1405) Resonance Region

The set of coupled Faddeev equations for the K¯NN–πΣN system is derived and the reaction K−d → πΣn, for which measurements are currently performed at J-PARC, is analyzed based on it. The present results in which the transition to the πΣN system is treated perturbatively show a peak in the Λ(1405) resonance region, but no clear enhancement above the K¯N threshold as suggested by the preliminary data of the J-PARC experiment. We point out that the observed enhancement originates from the quasi-free scattering between the incident K− and one of the nucleons in the deuteron, and we argue for the necessity of including full πΣN three-body processes in a realistic calculation