Structure of Di-Ω Dibaryon

Previously, we extended our chiral SU(3) quark model to include the coupling between the quark and vector chiral fields Nucl. Phys. A 727 (2003) 321. Here we further study the structure of (ΩΩ)_ST=00 dibaryon in the extended chiral SU(3) quark model by solving a resonating group method equation. The vector meson exchanges effect, hidden colour channel and colour screening effect are investigated, respectively. The results show that the (ΩΩ)_ST=00 system is still the deeply bound state in the extended chiral SU(3) quark model in which the vector meson exchanges control the short-range quark--quark interaction, which is similar to the results obtained from the chiral SU(3) quark model. When the model space is enlarged by including the hidden colour channel, it is found that the energy of the hidden colour state |CC>_str=-6,ST=00 is much higher than that of the (ΩΩ)_ST=00 state, thus the CC channel has little effect on the binding energy of (ΩΩ)_ST=00 state. When the error function confinement potential is considered, the bound state property would not change largely. Further, scalar meson mixing is considered. No matter whether ^S=-18° or ideal mixing is taken, (ΩΩ)_ST=00 state is still a bound state.