Relativistic three-body calculations of a Y=1, , dibaryon

The πΛN–πΣN coupled-channel system with quantum numbers is studied in a relativistic three-body model, using two-body separable interactions in the dominant p-wave pion–baryon and YN channels. Three-body equations are solved in the complex energy plane to search for quasibound state and resonance poles, producing a robust narrow πΛN resonance about 10–20 MeV below the πΣN threshold. Viewed as a dibaryon, it is a quasibound state consisting of Σ(1385)N and Δ(1232)Y components. Comparison is made between the present relativistic model calculation and a previous, outdated nonrelativistic calculation which resulted in a πΛN bound state. Effects of adding a channel are studied and found insignificant. Possible production and decay reactions of this dibaryon are discussed.