Pionic Decay of a Possible d′ -Dibaryon

The pionic decay of a possible d -dibaryon in the process d → N + N + π is studied in the microscopic quark shell model and with a single-quark transition operator describing the transition q → q + π. For the d with quantum numbers J = 0, T = 0, we employ a six-quark shell-model wave function with a spatial sp[51]X-configuration and with N = 1 harmonic oscillator quanta. It is shown that the pionic decay width depends strongly on the mass and size of the d . In the case that the calculated d mass is close to the experimental one a small pionic decay width of Γπ ≈ 0.04 MeV is obtained. This is an order of magnitude smaller than the experimental Γ π ≃ 0.5 MeV. Two possibilities to improve the calculated width are suggested. The effect of the nonstatic correction term in the transition operator and the influence of the form factor at the decay vertex on the decay width are also discussed.