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arXiv 2205.04068hep-ph
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twist-4上电子正电子湮没过程的前后不对称性

The forward-backward asymmetry in the electron positron annihilation process at twist-4

W. Yang, C. Li

摘要:

实验上特别感兴趣的是在$Z^0$衰变中产生的带正电荷和负电荷的费米子的角分布的前后不对称性。这种不对称性的测量可以使这些费米子的中性电流耦合,即$Z^0$玻色子耦合的左手和右手费米子,分别独立的测定。然而,由于夸克的禁闭,很难确定夸克,特别是轻夸克的电弱相互作用。在强子产生电子正电子湮没过程中,部分子模型结合因子分解定理给出了可靠的近似描述。因此,在湮灭过程中的碎裂函数的术语来表示。本文考虑了包含电子正电子湮没过程中的矢量介子产生,并在强子水平上计算了前后不对称性。计算是在部分子模型中应用共线展开法在首阶扭度为4时进行的。我们注意到这一过程不仅为分析强子弱相互作用提供了一个工具,而且为理解强相互作用的部分子模型提供了一个机会。换句话说,这些结果可以用来同时检验电弱相互作用和强相互作用。

英文摘要:

A quantity of particular experimental interest is the forward-backward asymmetry in the angular distribution of positively and negatively charged fermions produced in $Z^0$ decays. Measurements of this asymmetry can enable independent determinations of the neutral-current couplings of these fermions, i.e. the $Z^0$ boson couplings for left- and right-handed fermions, respectively. Due to the quark confinement, however, it is difficult to determine the electroweak interactions of quarks, especially for light quarks. In the hadron production electron positron annihilation process, the parton model with factorization theorem gives a reliable approximate description. Quantities are thus expressed in terms of fragmentation functions in the annihilation process. In this paper, we consider the vector meson production in the inclusive electron positron annihilation process and calculate the forward-backward asymmetry in the hadronic level. Calculations are carried out by applying the collinear expansion in the parton model at leading order twist-4. We note here this process provides not only a tool for analyzing the hadronic weak interactions but also an opportunity for understanding the parton model of the strong interaction. In other words, the results can be used to test the electroweak and strong interactions simultaneously.

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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