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On the short-distance constraints from K_{L,S} -> mu^+ mu^-

Gino Isidori·Rene Unterdorfer
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Abstract

Motivated by new precise results on several $K_L$ decays, sensitive to the ${K_L \to γγ}$ form factor, we present a new analysis of the $K_L\to μ^+μ^-$ long-distance amplitude based on a semi-phenomenological approach. Particular attention is devoted to the evaluation of the uncertainties of this method and to the comparison with alternative approaches. Our main result is a conservative upper bound of $2.5 \times 10^{-9}$ on $B(K_L \to μ^+ μ^-)_{\rm short}$, which is compatible with the SM expectation and which provides significant constraints on new-physics scenarios. The possibility to extract an independent short-distance information from future searches on $K_S \to μ^+ μ^-$ is also briefly discussed.

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Gino Isidori, Rene Unterdorfer. 2003-11-06. On the short-distance constraints from K_{L,S} -> mu^+ mu^-. https://doi.org/10.1088/1126-6708%2F2004%2F01%2F009

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