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• 作者：Andrzej J. Buras ; Jean-Marc Gérard
• 刊名：The European Physical Journal C
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：77
• 期：1
• 全文大小：521KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Elementary Particles, Quantum Field Theory; Nuclear Physics, Heavy Ions, Hadrons; Quantum Field Theories, String Theory; Measurement Science and Instrumentation; Astronomy, Astrophysics and Cosmology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1434-6052
• 卷排序：77

文摘

Dispersive effects from strong \(\pi \pi \) rescattering in the final state interaction (FSI) of weak \(K\rightarrow \pi \pi \) decays are revisited with the goal to have a global view on their relative importance for the \(\Delta I=1/2\) rule and the ratio \(\varepsilon '/\varepsilon \) in the standard model (SM). We point out that this goal cannot be reached within a pure effective (meson) field approach like chiral perturbation theory in which the dominant current–current operators governing the \(\Delta I=1/2\) rule and the dominant density–density (four-quark) operators governing \(\varepsilon '/\varepsilon \) cannot be disentangled from each other. But in the context of a dual QCD approach, which includes both long-distance dynamics and the UV completion, that is, QCD at short-distance scales, such a distinction is possible. We find then that beyond the strict large N limit, N being the number of colours, FSIs are likely to be important for the \(\Delta I=1/2\) rule but much less relevant for \(\varepsilon '/\varepsilon \). The latter finding diminishes significantly hopes that improved calculations of \(\varepsilon '/\varepsilon \) would bring its SM prediction to agree with the experimental data, opening thereby an arena for important new physics contributions to this ratio.