TY  - JOUR
AU  - NA62 Collaboration (Cortina Gil, E. et al
AU  - Husek, T.
PY  - 2020
DA  - 2020//
TI  - Search for heavy neutral lepton production in K+ decays to positrons
T2  - Phys. Lett. B
JO  - Physics Letters B
SP  - 135599
EP  - 9pp
VL  - 807
PB  - Elsevier
AB  - 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).
SN  - 0370-2693
UR  - https://arxiv.org/abs/2005.09575
UR  - https://doi.org/10.1016/j.physletb.2020.135599
DO  - 10.1016/j.physletb.2020.135599
LA  - English
N1  - WOS:000571765700067
ID  - NA62CollaborationCortinaGil+Husek2020
ER  -