Abstract:
We study the questions of the existence and mass of the proposed $d' (IJ^P=00^-)$ dibaryon in the quark-delocalization, color-screening model (QDCSM). The transformation between physical and symmetry bases has been extended to the cases beyond the SU(2) orbital symmetry. Using parameters fixed by baryon properties and $NN$ scattering, we find a mild attraction in the $IJ^P=00^-$ channel, but it is not strong enough to form a deeply bound state as proposed for the $d'$ state. Nor does the (isospin) I=2 N$\Delta$ configuration have a deeply bound state. These results show that if a narrow dibaryon $d'$ state does exist, it must have a more complicated structure.

Abstract:
Dibaryon candidates with strangeness S=-2,-3,-4,-5,-6 are studied in terms of the extended quark delocalization and color screening model. The results show that there are only a few promising low lying dibaryon states: The H and di-Omega may be marginally strong interaction stable but model uncertainties are too large to allow any definitive statement. The SIJ=-3,1/2,2 N-Omega state is 62 MeV lower than the N-Omega threshold and 24 MeV lower than the Lambda-Xi-pi threshold. It might appear as a narrow dibaryon resonance and be detectable in the RHIC detector through the reconstruction of the vertex mass of the Lambda-Xi two body decay. The effects of explicit K and eta meson exchange have been studied and found to be negligible in this model. The mechanisms of effective intermediate range attraction, sigma meson exchange and kinetic energy reduction due to quark delocalization are discussed.

Abstract:
The Omega-Omega (SIJ=-6,0,0) dibaryon state is studied with the extended quark-delocalization color-screening model including a pi meson exchange tail, which reproduces the properties of the deuteron quantitatively. We find the mass of the di-Omega to be about 45 MeV lower than the Omega-Omega threshold. The effect of channel coupling due to the tensor force has been calculated and found to be small in this case. We have also studied the effect of other pseudoscalar meson exchanges and sensitivity to the short-range cutoff radius, r_0, for the meson exchanges.

Abstract:
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.

Abstract:
The mass estimate of the $d^* (IJ^P=03^+)$ dibaryon is improved by a dynamical calculation in the quark delocalization, color screening model. The partial decay width of $d^*$ into an $NN$ D-wave state is also obtained. The mass obtained is slightly larger than that obtained in adiabatic calculations, due to the anharmonicity of the effective potential between two $\Delta$'s. The value of the width obtained due to tensor one-gluon-exchange is about 5 MeV, comparable in magnitude to earlier results found using pion exchange.

Abstract:
An alternative method is applied to the study of nucleon-nucleon(NN) scattering phase shifts in the framework of extended quark delocalization, color-screening model(QDCSM), where the one-pion-exchange(OPE) with short-range cutoff is included.

Abstract:
Inspired by the discovery of the dibaryon $d^{*}$ and the experimental search of $N\Omega$ dibaryon with the STAR data, we study the strange dibaryon $N\Omega$ further in the framework of quark delocalization color screening model and chiral quark model. We have shown $N\Omega$ is a narrow resonance in $\Lambda\Xi$ D-wave scattering before. However, the $\Lambda$-$\Xi$ scattering data analysis is quite complicated. Here we calculate the low-energy $N\Omega$ scattering phase shifts, scattering length, effective range and binding energy to provide another approach of STAR data analysis. Our results show there exists an $N\Omega$ "bound" state, which can be observed by the $N$-$\Omega$ correlation analysis with RHIC and LHC data, or by the new developed automatic scanning system at J-PARC. Besides, we also find that the hidden color channel-coupling is important for the $N\Omega$ system to develop intermediate-range attraction.

Abstract:
We consider the effect of including quark delocalization and color screening, in the nonrelativistic quark cluster model, on baryon-baryon potentials and phase shifts. We find that the inclusion of these additional effects allows a good qualitative description of both.

Abstract:
We look for $\Delta\Delta$ and $N\Delta$ resonances by calculating $NN$ scattering phase shifts of two interacting baryon clusters of quarks with explicit coupling to these dibaryon channels. Two phenomenological nonrelativistic chiral quark models giving similar low-energy $NN$ properties are found to give significantly different dibaryon resonance structures. In the chiral quark model (ChQM), the dibaryon system does not resonate in the $NN$ $S$-waves, in agreement with the experimental SP07 $NN$ partial-wave scattering amplitudes. In the quark delocalization and color screening model (QDCSM), the $S$-wave NN resonances disappear when the nucleon size $b$ falls below 0.53 fm. Both quark models give an $IJ^P = 03^+$ $\Delta\Delta$ resonance. At $b=0.52 $fm, the value favored by baryon spectrum, the resonance mass is 2390 (2420) MeV for the ChQM with quadratic (linear) confinement, and 2360 MeV for the QDCSM. Accessible from the $^3D_3^{NN}$ channel, this resonance is a promising candidate for the known isoscalar ABC structure seen more clearly in the $pn$$\to $$d\pi\pi$ production cross section at 2410 MeV in the recent preliminary data reported by the CELSIUS-WASA Collaboration. In the isovector dibaryon sector, our quark models give a bound or almost bound $^5S_2^{\Delta\Delta}$ state that can give rise to a $^1D_2^{NN}$ resonance. None of the quark models used has bound $N\Delta$ $P$-states that might generate odd-parity resonances.

Abstract:
Possible $H$-like dibaryon states $\Lambda_{c}\Lambda_{c}$ and $\Lambda_{b}\Lambda_{b}$ are investigated within the framework of quark delocalization color screening model. The results show that the interaction between two $\Lambda_{c}$'s is repulsive, so it cannot be bound state by itself. However, the strong attraction in $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ channels and the strong channel coupling, due to the central interaction of one-gluon-exchange and one-pion-exchange, among $\Lambda_{c}\Lambda_{c}$, $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ push the energy of system below the threshold of $\Lambda_{c}\Lambda_{c}$ by $22$ MeV. The corresponding system $\Lambda_{b}\Lambda_{b}$ has the similar properties as that of $\Lambda_{c}\Lambda_{c}$ system, and a bound state is also possible in $\Lambda_{b}\Lambda_{b}$ system.