In this work we investigate the finite-size effects on the phase structure of a two-flavor four-fermion interaction model with a flavor-mixing four-body interaction and in the presence of a magnetic background, taking into account different boundary conditions. We employ mean-field approximation and Schwinger's proper-time method in a toroidal topology with antiperiodic and periodic boundary conditions. The chiral susceptibility and constituent quark masses are studied under the change of the relevant parameters: size of compactified coordinates, temperature, chemical potential and magnetic field strength, within the different scenarios of boundary conditions and the value of flavor-mixing parameter. The findings suggest that the thermodynamic behavior of this system is strongly affected by the combined effects of relevant variables, depending on the range of their change, the value of flavor-mixing parameter and the choice of boundary conditions.
NN Scattering Phase Shifts in a Chiral Constituent Quark Model
本文研究了手征组分夸克模型中的核子-核子相互作用，它成功地再现了重子谱。我们用共振群方法计算了3S 1和1 S 0相移。它们清楚地表明，在短距离存在一个强的排斥相互作用，由于夸克-夸克相互作用的自旋-味道对称性和两个相互作用的核子之间的夸克交换。一个sigma交换夸克-夸克相互作用，提供了一个中程吸引力，有助于更接近实验相移。
The newly confirmed pentaquark state $P_c(4312)$ has been treated as a weakly bound $(Σ_c\bar{D})$ state by a well-established chiral constituent quark model and by a dynamical calculation on quark degrees of freedom where the quark exchange effect is accounted for. The obtained mass $4308$ MeV agrees with data. In this work, the selected strong decays of the $P_c(4312)$ state are studied with the obtained wave function. It is shown that the width of the $Λ_c\bar{D}^*$ decay is overwhelmed and the branching ratios of the $p\,η_c$ and $p\,J/ψ$ decays are both less than 1 percentage.
Spectrum of the low-lying $Ω_{cc}$ resonances with negative parity, which are assumed to be dominated by $sccq\bar{q}$ pentaquark components, is investigated using the chiral constituent quark model. Energies of the $Ω_{cc}$ resonances are obtained by considering the hyperfine interaction between quarks by exchanging Goldstone boson. Possible $sccq\bar{q}$ configurations with spin-parity $1/2^{-}$, $3/2^{-}$ and $5/2^{-}$ are taken into account. Numerical results show that the lowest $Ω_{cc}$ resonances with negative parity may lie at $4050 \pm 100$ MeV. In addition, the transitions of the $Ω_…
Recently, Belle Collaboration reported a new exotic state $Y(4620)$ with mass at 4625.9 MeV in the positronium annihilation process. Inspired by experiment, we study the tetraquark system $c\bar{s}s\bar{c}$ with quantum numbers $J^{P}=1^{-}$ in the framework of chiral constituent quark model with the help of Gaussian expansion method. Two structures, diquark-antidiquark and meson-meson, with all possible color and spin configurations are considered. The result shows that no bound state can be formed. To investigate the possible resonance states, the real scaling method is employed. Several res…
We have performed a study of the isovector, octet and singlet axial charges of the proton in an extended chiral constituent quark model, where all the possible $uudq\bar{q}$~($q=u,d,s$) five-quark Fock components in the proton wave function are taken into account. The $^3P_0$ quark-antiquark creation mechanism is assumed to account for the transition coupling between three- and five-quark components in proton, and the corresponding transition coupling strength is fixed by fitting the intrinsic sea flavor asymmetry $\bar{d}-\bar{u}$ data for proton. Accordingly, with all the parameters fixed by…
We estimate here chiral susceptibility at finite temperature within the framework of the Nambu-Jona-Lasinio model (NJL) using the Wigner function approach. We also estimate it in the presence of chiral chemical potential ($μ_5$) as well as a non vanishing magnetic field ($B$). We use medium separation regularization scheme (MSS) to calculate the chiral condensate and corresponding susceptibility. It is observed that for a fixed value of chiral chemical potential ($μ_5$), transition temperature increases with the magnetic field. While for the fixed value of the magnetic field, transition temper…
