标准模型中ε '/ε'的解剖结构得到改善
Improved anatomy of epsilon'/epsilon in the Standard Model
摘要：
本文给出了标准模型（SM）中ε ′/ε ′比值的一种新的分析方法，该方法使用了一种与Q_4、Q_9和Q_10算符的前导（V-A）×（V-A）QCD企鹅和EW企鹅强子矩阵元的值明显无关的形式，并适用于SM以及具有相同算符结构的扩展。它是有效的假设下，SM准确地描述了CP守恒K -> π π振幅的数据。由于这一点以及现在可以得到的CKM和夸克质量参数的高精度，高精度的ε '/ε只取决于两个非微扰参数，B_6^（1/2）和B_8^（3/2），以及微扰可计算的威尔逊系数。在SM中，我们能够从CP守恒的数据中单独确定强子矩阵元<Q_4>_0，比目前用格点量子色动力学所能确定的要精确得多。利用RBC-UKQCD合作组最近的结果，我们得到ε ′/ε ′ = 0.57+-0.19和B_8^（3/2）= 0.76+-0.05。（1.9 ± 4.5）10^-4，比最近RBC-UKQCD预测的精确得多，比实验值低2.9 σ（16.6+-2.3）10^-4，误差完全由B_6^（1/2）上的误差控制。即使完全丢弃格点输入，但采用最近从大N方法获得的界B_6^（1/2）<= B_8^（3/2）<= 1，发现SM值比实验值低2 σ以上。当B_6^（1/2）= B_8^（3/2）= 1时，在一个σ内改变所有其他参数，我们得到ε '/ε =（8.6+-3.2）10^-4。我们提出了一个详细的解剖的各种SM的不确定性，包括所有子领先的强子矩阵元素，简要地评论低估SM的贡献的可能性，以及我们的结果对新的物理模型的影响。
英文摘要：
We present a new analysis of the ratio epsilon'/epsilon within the Standard Model (SM) using a formalism that is manifestly independent of the values of leading (V-A)x(V-A) QCD penguin, and EW penguin hadronic matrix elements of the operators Q_4, Q_9, and Q_10, and applies to the SM as well as extensions with the same operator structure. It is valid under the assumption that the SM exactly describes the data on CP-conserving K -> pi pi amplitudes. As a result of this and the high precision now available for CKM and quark mass parameters, to high accuracy epsilon'/epsilon depends only on two non-perturbative parameters, B_6^(1/2) and B_8^(3/2), and perturbatively calculable Wilson coefficients. Within the SM, we are separately able to determine the hadronic matrix element <Q_4>_0 from CP-conserving data, significantly more precisely than presently possible with lattice QCD. Employing B_6^(1/2) = 0.57+-0.19 and B_8^(3/2) = 0.76+-0.05, extracted from recent results by the RBC-UKQCD collaboration, we obtain epsilon'/epsilon = (1.9+-4.5) 10^-4, substantially more precise than the recent RBC-UKQCD prediction and 2.9 sigma below the experimental value (16.6+-2.3) 10^-4, with the error being fully dominated by that on B_6^(1/2). Even discarding lattice input completely, but employing the recently obtained bound B_6^(1/2) <= B_8^(3/2) <= 1 from the large-N approach, the SM value is found more than 2 sigma below the experimental value. At B_6^(1/2) = B_8^(3/2) = 1, varying all other parameters within one sigma, we find epsilon'/epsilon = (8.6+-3.2) 10^-4. We present a detailed anatomy of the various SM uncertainties, including all sub-leading hadronic matrix elements, briefly commenting on the possibility of underestimated SM contributions as well as on the impact of our results on new physics models.
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。
