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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Search for heavy neutral lepton production in K+ decays to positrons
AU - NA62 Collaboration
AU - Carmignani, Joe
AU - Jones, Roger William Lewis
AU - Ruggiero, Giuseppe
AU - Dainton, John
PY - 2020/8/10
Y1 - 2020/8/10
N2 - A search for heavy neutral lepton (N) production in K+→e+Ndecays 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.
AB - A search for heavy neutral lepton (N) production in K+→e+Ndecays 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.
U2 - 10.1016/j.physletb.2020.135599
DO - 10.1016/j.physletb.2020.135599
M3 - Journal article
VL - 807
JO - Physics Letters B
JF - Physics Letters B
SN - 0370-2693
M1 - 135599
ER -