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arXiv 0907.5566hep-ph
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具有协变和光阵面组分夸克模型的π介子广义部分子分布

Pion Generalized Parton Distributions with covariant and Light-front constituent quark models

T. Frederico, E. Pace, B. Pasquini, G. Salmé

摘要:

我们研究了在类空区域中,夸克-强子和夸克-光子顶点的不同处理方法对π介子非螺旋翻转广义部分子分布的模型依赖性。为了获得有关价区和非价区贡献的信息,我们比较了从i)具有裸夸克-光子顶点的解析协变模型,ii)通过微观矢量介子模型修饰夸克-光子顶点的光阵面方法和iii)基于相对论哈密顿动力学的光阵面方法获得的类空动量转移的结果。我们的比较导致推断相同的动力学机制,在短距离的单胶子交换优势,作为一个源的电磁形状因子在大动量转移和部分子分布接近端点。预期的共线行为的广义部分子分布在高动量转移,即最大的$x\sim 1$,也说明了,独立于不同的方法。最后与最近的引力形状因子的晶格计算进行了比较。

英文摘要:

We investigate the model dependence of no-helicity flip generalized parton distribution of the pion upon different approaches for the quark-hadron and quark-photon vertexes, in the spacelike region. In order to obtain information on contributions from both the valence and non-valence regions, we compare results for spacelike momentum transfers obtained from i) an analytic covariant model with a bare quark-photon vertex, ii) a Light-front approach with a quark-photon vertex dressed through a microscopic vector-meson model and iii) a Light-front approach based on the Relativistic Hamiltonian Dynamics. Our comparisons lead to infer the same dynamical mechanism, the one-gluon-exchange dominance at short distances, as a source of both the electromagnetic form factor at large momentum transfer and the parton distribution close to the end-points. The expected collinear behavior of the generalized parton distributions at high momentum transfer, i.e. a maximum for $x\sim 1$, is also illustrated, independently of the different approaches. Finally a comparison with recent Lattice calculations of the gravitational form factors is presented.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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