Search for heavy neutral lepton production in K%2b decays to positrons Article uri icon

abstract

  • A search for heavy neutral lepton (N) production in K%2b→e%2bN 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 |Ue4|2 are established at the level of 10−9 over most of the accessible heavy neutral lepton mass range 144–462 MeV/c2, with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The |Ue4|2 range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/c2. © 2020 The Author(s)

authors

publication date

  • 2020-01-01

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