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The two-channel photoproductions of $\gamma p \to K^{*+} \Sigma^{0}$ and $\gamma p \to K^{*0} \Sigma^{+}$ are investigated based on an effective Lagrangian approach at the tree-level Born approximation. In addition to the $t$-channel $K$, $\kappa$, $K^*$ exchanges, the $s$-channel nucleon ($N$) and $\Delta$ exchanges, the $u$-channel $\Lambda$, $\Sigma$, $\Sigma^*$ exchanges, and the generalized contact term, we try to take into account the minimum number of baryon resonances in constructing the reaction amplitudes to describe the experimental data. It is found that by including the $\Delta(1905)5/2^+$ resonance with its mass, width, and helicity amplitudes taken from the Review of Particle Physics [Particle Data Group, C. Patrignani {\it et al.}, Chin. Phys. C {\bf 40}, 100001 (2016)], the calculated differential and total cross sections for these two reactions are in good agreement with the experimental data. An analysis of the reaction mechanisms shows that the cross sections of $\gamma p \to K^{*+}\Sigma^{0}$ are dominated by the $s$-channel $\Delta(1905)5/2^+$ exchange at low energies and $t$-channel $K^*$ exchange at high energies, with the $s$-channel $\Delta$ exchange providing significant contributions in the near-threshold region. For $\gamma p \to K^{*0}\Sigma^{+}$, the angular dependences are dominated by the $t$-channel $K$ exchange at forward angles and the $u$-channel $\Sigma^*$ exchange at backward angles, with the $s$-channel $\Delta$ and $\Delta(1905)5/2^+$ exchanges making considerable contributions at low energies. Predictions are given for the beam, target, and recoil asymmetries for both reactions., Comment: 11 pages, 8 figures, version published in PRC. arXiv admin note: text overlap with arXiv:1704.04562

A dynamical investigation of the nucleon-nucleon (NN) interaction by using the resonating group method (RGM) in a chiral SU(3) quark model has been revisited. The considered quark-quark interaction includes, besides the one-gluon exchange (OGE) and the phenomenological confinement potential, the nonet scalar and pseudoscalar meson exchanges derived from the spontaneous SU(3) chiral symmetry breaking. The physical consistency requirement that the wave functions of single baryons satisfy the minimums of the Hamiltonian has been strictly imposed in determination of the model parameters. The calculated masses of the octet and decuplet baryon ground states, the binding energy of the deuteron, and the NN scattering phase shifts up to a total angular momentum J=6 are in satisfactory agreement with the experiments., Comment: 14 pages, 10 figures, version published in PRD

The high-precision cross-section data for the reaction $\gamma p \to K^{*+}\Lambda$ reported by the CLAS Collaboration at the Thomas Jefferson National Accelerator Facility have been analyzed based on an effective Lagrangian approach in the tree-level approximation. Apart from the $t$-channel $K$, $\kappa$, $K^*$ exchanges, the $s$-channel nucleon ($N$) exchange, the $u$-channel $\Lambda$, $\Sigma$, $\Sigma^*(1385)$ exchanges, and the generalized contact term, the contributions from the near-threshold nucleon resonances in the $s$-channel are also taken into account in constructing the reaction amplitude. It is found that, to achieve a satisfactory description of the differential cross section data, at least two nucleon resonances should be included. By including the $N(2060){5/2}^-$ resonance, which is responsible for the shape of the angular distribution near the $K^*\Lambda$ threshold, and one of the $N(2000){5/2}^+$, $N(2040){3/2}^+$, $N(2100){1/2}^+$, $N(2120){3/2}^-$ and $N(2190){7/2}^-$ resonances, one can describe the cross-section data quite well, with the fitted resonance masses and widths compatible with those advocated by the Particle Data Group. The resulted predictions of the beam, target, and recoil asymmetries are found to be quite different from various fits, indicating the necessity of the spin observable data for $\gamma p \to K^{*+}\Lambda$ to further pin down the resonance contents and associated parameters in this reaction., Comment: 19 pages, 14 figures

We confirm our previous prediction of a $d^*$ state with $I(J^P)=0(3^+)$ [Phys. Rev. C 60, 045203 (1999)] and report for the first time based on a microscopic calculation that $d^*$ is a hexaquark dominated exotic state as it has about 2/3 hidden color (CC) configurations. By performing a more elaborate dynamical coupled-channels investigation of the $\Delta\Delta$-CC system within the framework of resonating group method (RGM) in a chiral quark model, we found that the $d^*$ state has a mass of about 2.38-2.42 GeV, a root-mean-square radius (RMS) of 0.76-0.88 fm, and a CC fraction of 66%-68%. The last ensures that the $d^*$ has a rather narrow width which, together with the quantum numbers and our calculated mass, is consistent with the newly observed resonance-like structure ($M\approx 2380$ MeV, $\Gamma\approx 70$ MeV) in double-pionic fusion reactions reported by WASA-at-COSY Collaboration., Comment: 4 pages, 2 figures

We perform a systematic study of the bound state problem of $D\bar{D}$ and $B\bar{B}$ systems by using effective interaction in our chiral quark model. Our results show that both the interactions of $D\bar{D}$ and $B\bar{B}$ states are attractive, which consequently result in $I^G(J^{PC})=0^+(0^{++})$ $D\bar{D}$ and $B\bar{B}$ bound states., Comment: arXiv admin note: substantial text overlap with arXiv:1204.3959

We perform a systematic study of $B\bar{B}^*$, $B^*\bar{B}^*$, $D\bar{D}^*$ and $D^*\bar{D}^*$ systems by using effective interaction in our chiral quark model. Our results show that the interactions of $B\bar{B}^*$, $B^*\bar{B}^*$, $D\bar{D}^*$ and $D^*\bar{D}^*$ states are attractive, which consequently result in $B\bar{B}^*$, $B^*\bar{B}^*$, $D\bar{D}^*$ and $D^*\bar{D}^*$ bound states. The recent observed exotic-like hadrons of $Z_b(10610)$ and $Z_b(10650)$ are, therefore in our approach, interpreted as loosely bound states of $B\bar{B}^*$ and $B^*\bar{B}^*$, while X(3872) and Y(3940) are $D\bar{D}^*$ and $D^*\bar{D}^*$ molecule states, respectively., Comment: 8 pages, 4 figures

A dynamical coupled-channel study of K* K*bar state with isospin 0 and omega phi state is performed within 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 octet and decuplet baryon ground states, the binding energy of the deuteron, the nucleon-nucleon (NN) scattering phase shifts, and the hyperon-nucleon (YN) cross sections. The results show that the interactions of K* K*bar states are attractive, which consequently result in K* K*bar bound states with the binding energies of about 10-70 MeV, and contrarily, no omega phi bound state is obtained. The channel coupling effect of K* K*bar and omega phi is found to be considerably large, which makes the binding of K* K*bar 5-45 MeV deeper. The plausible interpretation of f_0(1710) and X(1812) being K* K*bar dominated states is briefly discussed., Comment: 7 pages, 4 figures

The S-wave Sigma_c Dbar and Lambda_c Dbar states with isospin I=1/2 and spin S=1/2 are dynamically investigated within the framework of a chiral constituent quark model by solving a resonating group method (RGM) equation. The results show that the interaction between Sigma_c and Dbar is attractive, which consequently results in a Sigma_c Dbar bound state with the binding energy of about 5-42 MeV, unlike the case of Lambda_c Dbar state, which has a repulsive interaction and thus is unbound. The channel coupling effect of Sigma_c Dbar and Lambda_c Dbar is found to be negligible due to the fact that the gap between the Sigma_c Dbar and Lambda_c Dbar thresholds is relatively large and the Sigma_c Dbar and Lambda_c Dbar transition interaction is weak., Comment: 7 pages,2 figures. arXiv admin note: text overlap with arXiv:nucl-th/0606056 by other authors

A preliminary investigation of the anti-K N interaction is performed within a chiral constituent quark model by solving the resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the S-, P-, D-, F-wave KN scattering phase shifts. The channel-coupling between anti-K N, pi Lambda and pi Sigma is considered, and the scattering phase shifts as well as the bound-state problem of anti-K N are dynamically studied. The results show that the S-wave anti-K N interaction in the isospin I=0 channel is attractive, and in the extended chiral SU(3) quark model such an attraction can make for an anti-K N bound state, which appears as a pi Sigma resonance in the coupled-channel calculation, while the chiral SU(3) quark model cannot accommodate the existence of an anti-K N bound state. It seems that the vector meson exchanges are necessary to be introduced in the quark-quark interactions if one tries to explain the Lambda(1405) as an anti-K N bound state or a pi Sigma - anti-K N resonance state., Comment: 4 pages, 6 figures

The energies of the low-lying isoscalar and isovector ud anti-s anti-s configurations with spin-parity J^P=0^+, 1^+, and 2^+ are calculated in a non-relativistic constituent quark model by use of the variational method. The contributions of various parts of the quark-quark interacting potentials including the s-channel interaction are investigated, and the effect of different forms of confinement potential is examined. The model parameters are determined by the same method as in our previous work, and they still can satisfactorily describe the nucleon-nucleon scattering phase shifts and the hyperon-nucleon cross sections. The parameters of the s-channel interaction are fixed by the masses of K and K^* mesons, for which the size parameter is taken to be two possible values. When it is chosen as the same as baryons', the numerical results show that the masses of all the ud anti-s anti-s configurations are higher than the corresponding meson-meson thresholds. But when the size parameter for the K and K^* mesons is adjusted to be smaller than that for the baryons, the ud anti-s anti-s configuration with I=0 and J^P=1^+ is found to lie lower than the K^*K^* threshold, furthermore, this state has a very small KK^* component and the interaction matrix elements between this state and KK^* is comparatively small, thus its coupling to the KK^* channel will consequently be weak and it might be regarded as a possible tetraquark candidate., Comment: 17 pages, 1 figure

The structure of Omega-pi state with isospin I=1 and spin-parity J^p=3/2^- 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 Omega-pi state has an attractive interaction, and in the extended chiral SU(3) quark model such an attraction can make for an Omega-pi quasi-bound state with the binding energy of about several MeV., Comment: 11 pages, 1 figure

The new members of the charm-strange family $D_{sJ}^{*}(2317)$, $D_{sJ}(2460)$ and $D_s(2632)$, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to this issue. Most of authors suggest that they are not the conventional $c\bar s$ quark model states, but possibly are four-quark states, molecule states or mixtures of a P-wave $c\bar s$ and a four-quark state. In this work, we follow the four-quark-state picture, and study the masses of $cn\bar n\bar s/cs\bar s\bar s$ states ($n$ is $u$ or $d$ quark) in the chiral SU(3) quark model. The numerical results show that the mass of the mixed four-quark state ($cn\bar n\bar s/cs\bar s\bar s$) with spin parity $J^P=0^{+}$ might not be $D_s(2632)$. At the same time, we also conclude that $D_{sJ}^{*}(2317)$ and $D_{sJ}(2460)$ cannot be explained as the pure four-quark state., Comment: 20 pages