arXiv 0912.06912009-12hep-lat

SU中的强子-强子相互作用（2）格点量子色动力学

Hadron-hadron interaction from SU(2) lattice QCD

Toru T. Takahashi, Yoshiko Kanada-En'yo

备注：: 14 pages, 20 figures
发表信息：: Phys.Rev.D82:094506,2010
DOI：: 10.1103/PhysRevD.82.094506

摘要：

本文从欧氏格点上的Bethe-Salpeter振幅计算了双色格点量子色动力学中强子间的相互作用。模拟是在猝灭SU（2）QCD中进行的，在$β= 2.45$处有格构规范作用量，在Wilson夸克作用量下进行。我们主要研究双标量夸克的S波散射态。通过对不同夸克质量的不同味组合的评价，我们试图找出强子相互作用中的成分。在两个标量双夸克（SU（2）系统中最轻的重子$u Cγ_5 d$）之间，我们观察到了短程排斥，尽管夸克的质量并不很轻。我们定义并计算了相互作用中的“夸克交换部分”，它是通过增加夸克交换图，或等价地，通过在某些夸克之间引入泡利阻塞而引入的。短程区的排斥力只产生于“夸克交换部分”，当不画夸克交换图时排斥力消失。我们发现，在轻夸克质量区，排斥强度增大，其夸克质量依赖性类似于或略强于单胶子交换过程的色磁相互作用.夸克间的色磁相互作用是排斥的起源，这与组分-夸克模型的观点是定性一致的。我们还发现了一种普适的长程吸引力，它可以进入两个标量双夸克的任意味通道，其相互作用范围和强度与夸克质量无关。每个分量中相互作用范围的弱夸克质量依赖性意味着介子交换贡献很小且次主导，而其他贡献{ \it ex.}味交换过程，色库仑或色磁相互作用，被认为是占主导地位的，在夸克质量范围内，我们评估。

英文摘要：

We evaluate interhadron interactions in two-color lattice QCD from Bethe-Salpeter amplitudes on the Euclidean lattice. The simulations are performed in quenched SU(2) QCD with the plaquette gauge action at $β= 2.45$ and the Wilson quark action. We concentrate on S-wave scattering states of two scalar diquarks. Evaluating different flavor combinations with various quark masses, we try to find out the ingredients in hadronic interactions. Between two scalar diquarks ($u Cγ_5 d$, the lightest baryon in SU(2) system), we observe repulsion in short-range region, even though present quark masses are not very light. We define and evaluate the "quark-exchange part" in the interaction, which is induced by adding quark-exchange diagrams, or equivalently, by introducing Pauli blocking among some of quarks. The repulsive force in short-distance region arises only from the "quark-exchange part", and disappears when quark-exchange diagrams are omitted. We find that the strength of repulsion grows in light quark-mass regime and its quark-mass dependence is similar to or slightly stronger than that of the color-magnetic interaction by one-gluon-exchange (OGE) processes. It is qualitatively consistent with the constituent-quark model picture that a color-magnetic interaction among quarks is the origin of repulsion. We also find a universal long-range attractive force, which enters in any flavor channels of two scalar diquarks and whose interaction range and strength are quark-mass independent. The weak quark-mass dependence of interaction ranges in each component implies that meson-exchange contributions are small and subdominant, and the other contributions, {\it ex.} flavor exchange processes, color-Coulomb or color-magnetic interactions, are considered to be predominant, in the quark-mass range we evaluated.

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