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arXiv · 2202.00331

Searches for lepton number violating $K^+\toπ^-(π^0)e^+e^+$ decays

NA62 collaboration
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Abstract

Searches for lepton number violating $K^+\toπ^-e^+e^+$ and $K^+\toπ^-π^0e^+e^+$ decays have been performed using the complete dataset collected by the NA62 experiment at CERN in 2016-2018. Upper limits of $5.3\times 10^{-11}$ and $8.5\times 10^{-10}$ are obtained on the decay branching fractions at 90% confidence level. The former result improves by a factor of four over the previous best limit, while the latter result represents the first limit on the $K^+\toπ^-π^0e^+e^+$ decay rate.

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NA62 collaboration. 2022-05-12. Searches for lepton number violating $K^+\toπ^-(π^0)e^+e^+$ decays. https://doi.org/10.1016/j.physletb.2022.137172

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