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arXiv · hep-ph/9407342

Parity Violating Longitudinal Muon Polarization in $K^+\toπ^+μ^+μ^-$ Beyond Leading Logarithms

G. Buchalla·A. J. Buras
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Abstract

We generalize the existing analyses of the parity violating muon polarization asymmetry $Δ_{LR}$ in $K^+\toπ^+μ^+μ^-$ beyond the leading logarithmic approximation. The inclusion of next--to--leading QCD corrections reduces the residual dependence on the renormalization scales, which is quite pronounced in the leading order. This leads to a considerably improved accuracy in the perturbative calculation of the short distance dominated quantity $Δ_{LR}$. Accordingly this will also allow to obtain better constraints on the Wolfenstein parameter $\varrho$ from future measurements of $Δ_{LR}$. For $-0.25\leq \varrho \leq 0.25$, $V_{cb}=0.040\pm 0.004$ and $m_t=(170\pm 20)GeV$ we find $3.0\cdot 10^{-3}\leq |Δ_{LR}|\leq 9.6\cdot 10^{-3}$.

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G. Buchalla, A. J. Buras. 1994-07-20. Parity Violating Longitudinal Muon Polarization in $K^+\toπ^+μ^+μ^-$ Beyond Leading Logarithms. https://doi.org/10.1016/0370-2693(94)00997-x

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