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arXiv hep-ph/9306323hep-phnucl-th
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夸克流两点函数的低能行为

Low--Energy Behavior of Two--Point Functions of Quark Currents

Johan Bijnens, Eduardo de Rafael, Hanqing Zheng

摘要:

我们讨论了低能量和中能量下的向量、轴向量、标量和赝标量两点函数。我们首先回顾什么是已知的手征微扰理论,以及从扩展的Nambu-Jona-Lasinio(ENJL)模型的参考文献\cite{12}的上下文中的热核膨胀。在这项工作中,我们推导出这些两点函数的所有订单的动量和领先的顺序在$1/N_c$。我们发现一个改进的高能量的行为和参数化的一般方法,显示一些两点函数,这也是有效的存在下的胶子相互作用之间的关系。实验上已知的光谱函数和我们得到的光谱函数的形状之间的相似性,大大提高了那些由通常的组分夸克模型预测。我们还得到了与正则化方案无关的标量质量$M_S = 2 M_Q$。最后,我们对ENJL模型中的一个非轻子矩阵元--$π^+-π^0$电磁质量差进行了详细的计算,并与实验值进行了比较,结果吻合较好。

英文摘要:

We discuss vector, axial-vector, scalar and pseudoscalar two-point functions at low and intermediate energies. We first review what is known from chiral perturbation theory, as well as from a heat kernel expansion within the context of the extended Nambu-Jona-Lasinio (ENJL) model of ref. \cite{12}. In this work we derive then these two-point functions to all orders in the momenta and to leading order in $1/N_c$. We find an improved high-energy behaviour and a general way of parametrizing them that shows relations between some of the two-point functions, which are also valid in the presence of gluonic interactions. The similarity between the shape of the experimentally known spectral functions and the ones we derive, is greatly improved with respect to those predicted by the usual constituent quark like models. We also obtain the scalar mass $M_S = 2 M_Q$ independent of the regularization scheme. In the end, we calculate fully an example of a nonleptonic matrix element in the ENJL--model, the $π^+-π^0$ electromagnetic mass difference and find good agreement with the measured value.

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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