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arXiv · 1712.00297

Search for heavy neutral lepton production in $K^+$ decays

NA62 collaboration
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Abstract

A search for heavy neutral lepton production in $K^+$ decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the $10^{-7}$ to $10^{-6}$ level are established on the elements of the extended neutrino mixing matrix $|U_{\ell 4}|^2$ ($\ell=e,μ$) for heavy neutral lepton mass in the range $170-448~{\rm MeV}/c^2$. This improves on the results from previous production searches in $K^+$ decays, setting more stringent limits and extending the mass range.

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NA62 collaboration. 2018-01-12. Search for heavy neutral lepton production in $K^+$ decays. https://doi.org/10.1016/j.physletb.2018.01.031

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