Zhang Zong-Ye

Nucleon-meson vertex functions and isobar-meson vertex functions from the quark potential model

Abstract In this paper, we have derived a nonrelativistic transition potential V q-qq q from one-gluon-exchange theory and calculated the matrix elements of the nucleon-meson vertices and isobar-meson vertices from this transition potential by using the generator coordinate method. The coupling constants of the vertices are in agreement with the experimental data and the form factors of the vertices are much like gaussian functions.

Nuclear Matter in a Chiral SU(3) Quark Mean-Field Model

A quark meson coupling model based on SU(3)L × SU(3)R symmetry and scale invariance is proposed.The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to investigating the nuclear matter at finite temperature and density. The effective baryon masses, compression modulus and hyperon potentials are all reasonable. The critical temperature ofliquid-gas phase transition is also calculated in this model.``

Color screening effect in the quark potential model

By using the color confinement potential which includes the color screening effect, we studied the baryon spectra and the nucleon-nucleon interaction. The results show that the color screening effect not only improves the baryon spectrum calculation, but also can solve the long-tail problem of the color Van der Waals force. A part of the medium attraction of the nuclear force can be obtained from the color Van der Waals force.

Ωω States in a Chiral Quark Model

The structures of Ωω states with spin-parity Jp = 5/2−, 3/2−, and 1/2− are dynamically studied in both the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon (NN) scattering phase shifts, and the hyperon-nucleon (YN) cross sections. The calculated results show that the Ωω state has an attractive interaction, and in the extended chiral SU(3) quark model such attraction can make for a Ωω quasi-bound state with spin-parity Jp = 3/2− or 5/2− and the binding energy of about several MeV.

The structure of deltaron dibaryon

We discuss the structure of deltaron dibaryon in the chiral quark model. The energy of deltaron is obtained by considering the coupling of the and CC (hidden color) channels. It is shown that the mass of deltaron is lower than the mass of but higher than the mass of .

Nucleon-nucleon interaction with a flat bottom linear confinement potential in the Quark model

Nucleon-nucleon interaction is studied in the non-relativistic quark model with a flat bottom linear confinement potential. The results are consistent with the calculated ones from the lattice quantum chromodynamics. The quark-quark interaction also consists of those caused by the one gluon exchange and the one pion exchange. The phenomenological sigma meson exchange between two nucleons is also included to fit the S-wave N-N scattering data. The calculated NN channel S-wave phase shifts show that the flat bottom linear confinement potential can provide part of the medium range attraction.

Nucleon-Meson Vertex Interaction from one Gluon Exchange Transition Potential —the Coupling Constants and the form Factors

In this paper the matrix elements of the nucleon-meson vertexes from one gluon exchange transition potential are calculated by using the generator coordinate method. We have found that the coupling constants of the nucleon-meson vertexes are roughly in agreement with the experimental data and the form factors of the vertexes are quite like the Gauss functions.

KN Phase Shifts in Chiral SU(3) Quark Model

The isospin and kaon-nucleon S and P partial waves phase shifts have been studied in the chiral SU(3) quark model by solving a resonating group method equation. When the parameters of the chiral fields are taken in a reasonable region, the numerical results of S-wave are in good agreement with the experimental data, and the P-wave phase shifts can also be explained qualitatively by the calculation of only central force considered.

A Prediction of a New Dibaryon System (Ω-Ω-)Jπ=0+

The structure of a new dibaryon (ΩΩ)0+ is studied and predicted in the framework of the chiral SU(3) quark model by solving a resonating group method equation. The binding energy of this dibaryon is around 100 MeV, the mean root square of the distance between two Ωs is 0.84 fm and the preliminary estimated mean lifetime is about two times longer than that of the free Ω. All these interesting properties and also the two negative charge units it carried could make it be easily identified experimentally in the heavy-ion collision process. The production probability of this new dibaryon in 158A GeV Pb+Pb collision is estimated using the thermal model, which is of the order of 10-6 to 10-5 per event; And it is expected, that with the increase of temperature, the production rate will also be increased.

Influence of the ΔΔ channel with the FBL confinement on the nn-interaction

The N-N interaction is studied in the framework of non-relativistic quark model using the resonating group method (RGM). The ΔΔ channel is taken into account in addition to the NN channel. The calculated S-wave phase shifts show that the channel coupling effect is increased if the quadratic or the linear confinement is replaced by the flat-bottom-linear confinement. This result is quite different from that in the case of the quadratic confinement or the linear confinement, in which this channel coupling effect is negligible.