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Long vs. short distance dispersive two-photon K_L \to μ^+ μ^- amplitude

J. O. Eeg·K. Kumericki·I. Picek
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Abstract

We report on the calculation of the two-loop electroweak, two-photon mediated short-distance dispersive K_L \to μ^+μ^- decay amplitude. QCD corrections change the sign of this contribution and reduce it by an order of magnitude. The resulting amplitude enables us to provide a constraint on the otherwise uncertain long-distance dispersive amplitude.

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J. O. Eeg, K. Kumericki, I. Picek. 1999-01-21. Long vs. short distance dispersive two-photon K_L \to μ^+ μ^- amplitude. https://arxiv.org/abs/hep-ph/9901372

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