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arXiv 1306.1248hep-ph
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相对论点形式方法下的电弱强子结构

Electroweak hadron structure within a relativistic point-form approach

María Gómez-Rocha

摘要:

本文提出了一个计算任意组分夸克质量介子电弱结构的广义相对论框架。利用相对论性量子力学的点形式,对测量结构的物理过程,即电子-介子散射和半轻子弱衰变,作了庞加莱不变量处理.电磁流和弱介子流是从1-光子或1-W-交换振幅中提取的,这些振幅是由相应系统的Bakamjian-Thomas型质量算符产生的。这些电流的协变分解提供了电磁和弱(过渡)形状因子。该方法首次应用于重-轻系统的研究。集群可分性,这是固有的Bakamjian-Thomas建设的问题进行了讨论,并显示如何保持它们的控制。证明了电弱形状因子的重夸克极限导致了一个普适函数Isgur-Wise函数,证实了重夸克对称性的要求是满足的。这些结果进行了讨论,并与类似的计算在前面的形式的动力学。该方法被进一步应用到由动态粒子交换引起的束缚态的研究中。如何考虑延迟效应的粒子交换势的问题制定和它示出它们如何影响的结合能和波函数解的动态模型的氘核。在这项工作的最后,一个例子中的庞加莱组的Clebsch-Gordan系数的应用。给出了手征多重态的角动量分解的瞬时形式和波前形式。

英文摘要:

In this thesis a general relativistic framework for the calculation of the electroweak structure of mesons of arbitrary constituent-quark masses is presented. The physical processes in which the structure is measured, i.e. electron-meson scattering and semileptonic weak decays, are treated in a Poincaré invariant way by making use of the point-form of relativistic quantum mechanics. The electromagnetic and weak meson currents are extracted from the 1-photon or 1-W-exchange amplitudes that result from a Bakamjian-Thomas type mass operator for the respective systems. The covariant decomposition of these currents provides the electromagnetic and weak (transition) form factors. The formalism is first applied to the study of heavy-light systems. Problems with cluster separability, which are inherent in the Bakamjian-Thomas construction, are discussed and it is shown how to keep them under control. It is proved that the heavy-quark limit of the electroweak form factors leads to one universal function, the Isgur-Wise function, confirming that the requirements of heavy-quark symmetry are satisfied. These results are discussed and compared with analogous calculations in the front form of dynamics. The formalism is further applied to the study of bound states whose binding is caused by dynamical particle exchange. The problem of how to take into account retardation effects in the particle-exchange potential is formulated and it is shown how they affect the binding energy and wave-function solution for a dynamical model of the deuteron. At the end of this work an example where the Clebsch-Gordan coefficients of the Poincaré group are applied is presented. The angular momentum decomposition of chiral multiplets is given in the instant and in the front forms.

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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