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arXiv · hep-ph/9903230

A short look at epsilon'/epsilon

Y. -Y. Keum·U. Nierste·A. I. Sanda
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Abstract

We analyze the theoretical implications of the new KTeV measurement of direct CP-violation in K->pi pi decays. The result is found consistent with the Standard Model for low values of the strange quark mass m_s. If the hadronic parameters B_6^{(1/2)} and B_8^{(3/2)} satisfy 2 B_6^{(1/2)} - B_8^{(3/2)} < 2, as suggested by lattice and 1/N_c calculations, we find an upper bound of 110 MeV for m_s (2 GeV)$. We parametrize potential new physics contributions to ε'/εand illustrate their correlation with upper bounds on m_s. Finally we discuss a non-perturbative mechanism, which is not contained in the existing calculations of B_6^{(1/2)}. This mechanism enhances B_6^{(1/2)} and thereby leads to a better understanding of the Delta I=1/2 rule and the high measured value of Re (ε^\prime/ε)

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Y. -Y. Keum, U. Nierste, A. I. Sanda. 1999-03-12. A short look at epsilon'/epsilon. https://doi.org/10.1016/s0370-2693(99)00523-7

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