Quark delocalization, color screening, and dibaryons.

The quark delocalization and color screening model, a quark potential model, is used for a systematic search of dibaryon candidates in the u, d and s three flavor world. Color screening which appears in unquenched lattice gauge calculations and quark delocalization (which is similar to electron delocalization in molecular physics) are both included. Flavor symmetry breaking and channel coupling effects are studied. The model is constrained not only by baryon ground state properties but also by the N -N scattering phase shifts. The deuteron and zero energy di-nucleon resonance are both reproduced qualitatively. The model predicts two extreme types of dibaryonic systems: “molecular” like the deuteron, and highly delocalized six-quark systems among which only a few narrow dibaryon resonances occur in the u, d and s three flavor world. Possible high spin dibaryon resonances are emphasized.