In this paper we calculate the quark number susceptibility (QNS) of QCD at finite temperature under the rainbow-ladder and Ball-Chiu type truncation schemes of the Dyson-Schwinger approach. It is found that the difference between the result of the rainbow-ladder truncation and that of Ball-Chiu type truncation is small, which shows that the dressing effect of the quark-gluon vertex on the QNS at finite temperature is small. It is also found that at low temperature the quark number susceptibility is nearly zero and it increases sharply when the temperature approaches the chiral phase transition point. A comparison between the result in the present paper with those in the literature is made.
Calculation of tensor susceptibility beyond rainbow-ladder approximation of Dyson-Schwinger equations approach
本文推广了[Y. M. Shi，K. P. Wu，W. M. Sun，H. S. Zong，J. L. Ping，Phys. Lett. B $\bf{639}$，248（2006）]的方法与采用Ball-Chiu（BC）顶点的方法相比。研究了夸克胶子顶点的修饰效应对张量真空磁化率的影响。结果表明，与彩虹梯近似值相比，在BC顶点近似下得到的张量真空磁化率降低了约10%。这说明在DS方法中计算张量真空磁化率时，夸克胶子顶点的修饰效应并不大。
Correlation functions can be described by the corresponding equations, $viz.$, gap equation for quark propagator and the inhomogeneous Bethe-Salpeter equation for vector dressed-fermion-Abelian-gauge-boson vertex in which specific truncations have to be implemented. The general vector and axial-vector Ward-Green-Takahashi identities require these correlation functions to be interconnected, in consequence of this, truncations made must be controlled consistently. It turns out that if the rainbow approximation is assumed in gap equation, the scattering kernel in Bethe-Salpeter equation can adopt…
We suggest a framework based on the rainbow approximation to the Dyson-Schwinger and Bethe-Salpeter equations with effective parameters adjusted to lattice QCD data to calculate the masses of the ground and excited states of pseudo-scalar glueballs. The structure of the truncated Bethe-Salpeter equation with the gluon and ghost propagators as solutions of the truncated Dyson-Schwinger equations is analysed in Landau gauge. Both, the Bete-Salpeter and Dyson-Schwinger equations, are solved numerically within the same rainbow-ladder truncation with the same effective parameters which ensure consi…
总结了基于截断到阶梯彩虹水平的Dyson-Schwinger方程组的软QCD建模的最新进展。这种强子物理学的协变方法可以容纳夸克禁闭并实现QCD单圈重整化群行为。我们比较了缀饰夸克传播子，赝标和矢量介子质量作为夸克质量的函数，以及rho -> pi pi耦合到最近的晶格QCD数据。盖尔曼-奥克斯-伦纳关系与夸克质量增加的错误进行量化比较，在梯形彩虹戴森Schwinger模型内评估的精确的赝标质量关系。
We present the first dynamical calculation of the $ρ$-meson as a resonance in the Dyson-Schwinger/Bethe-Salpeter framework by including explicit two-pion exchange in addition to the t-channel one-gluon exchange of rainbow-ladder in the interaction kernel. The width is determined from the imaginary part of the resonance pole and is generated by the singularity structure of the integrand, treated by means of suitable path deformations. We find the resonant mass and width to be $640$ MeV and $100$ MeV respectively, corresponding to a coupling constant $g_{ρππ}=5.7$; repulsive corrections beyond r…
Analysis of a quenched lattice-QCD dressed-quark propagator
淬熄的格点量子色动力学关于缀饰夸克施温格函数的数据可以通过彩虹隙方程与缀饰胶子数据相关联，只要该方程的核在红外动量处具有比单独胶子所表现出的增强。所需的增强可以归因于夸克-胶子顶点的修饰。彩虹带隙方程的解表现出动力学手征对称性破缺，与禁闭相一致。能隙方程和相关的、保序的阶梯贝特-萨尔彼得方程给出了手征和物理π介子观测量的估计，表明这些量在猝灭理论中被严重低估了：|<bar-q q>| by a factor of two and f_pi by 30%.
