@Article{NA62CollaborationCortinaGil+Husek2020,
author="NA62 Collaboration (Cortina Gil, E. et al
and Husek, T.",
title="Search for heavy neutral lepton production in K+ decays to positrons",
journal="Physics Letters B",
year="2020",
publisher="Elsevier",
volume="807",
pages="135599--9pp",
abstract="A search for heavy neutral lepton (N) production in K+ -> e(+)N decays using the data sample collected by the NA62 experiment at CERN in 2017-2018 is reported. Upper limits of the extended neutrino mixing matrix element vertical bar U-e4 vertical bar(2) are established at the level of 10(-9) over most of the accessible heavy neutral lepton mass range 144-462 MeV/c(2), with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The vertical bar U-e4 vertical bar(2) range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/c(2).",
optnote="WOS:000571765700067",
optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=4544), last updated on Thu, 08 Oct 2020 08:54:09 +0000",
issn="0370-2693",
doi="10.1016/j.physletb.2020.135599",
opturl="https://arxiv.org/abs/2005.09575",
opturl="https://doi.org/10.1016/j.physletb.2020.135599",
language="English"
}