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arXiv · hep-ex/9504005

A Measurement of the Branching Ratio and Form Factor of K_L->mu mu gamma

M. B. Spencer et. al
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Abstract

We report on a measurement of the decay $K_L\rightarrowμ^+μ^-γ$ from Fermilab experiment E799. We observe $207$ candidate signal events with an estimated background of $10.5 \pm 4.0$ events and establish $B(K_L\rightarrowμ^+μ^-γ) = (3.23\pm 0.23(stat) \pm 0.19(sys))\times 10^{-7}$. This provides the first measurement of the $Kγγ^*$ form factor in the muonic Dalitz decay mode of the $K_L$.

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M. B. Spencer et. al. 1995-04-21. A Measurement of the Branching Ratio and Form Factor of K_L->mu mu gamma. https://doi.org/10.1103/physrevlett.74.3323

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