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arXiv · 2409.12981

First search for $K^+\to\pi^0\pi\mu e$ decays

NA62 collaboration
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Abstract

The first search for the lepton number violating decay $K^+\to\pi^0\pi^-\mu^+e^+$ and lepton flavour violating decays $K^+\to\pi^0\pi^+\mu^-e^+$, $K^+\to\pi^0\pi^+\mu^+e^-$ has been performed using a dataset collected by the NA62 experiment at CERN in 2016-2018. Upper limits of $2.9\times 10^{-10}$, $3.1\times 10^{-10}$ and $5.0\times 10^{-10}$, respectively, are obtained at 90% CL for the branching ratios of the three decays on the assumption of uniform phase-space distributions.

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NA62 collaboration. 2024-09-03. First search for $K^+\to\pi^0\pi\mu e$ decays. https://arxiv.org/abs/2409.12981

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