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 |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.
Search for heavy neutral lepton production in K+ decays to positrons / Ambrosino, F.; Corvino, M.; Massarotti, P.; Mirra, M.; Napolitano, M.; Saracino, G.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 807:(2020), p. 135599. [10.1016/j.physletb.2020.135599]
Search for heavy neutral lepton production in K+ decays to positrons
Ambrosino F.;Corvino M.;Massarotti P.;Napolitano M.;Saracino G.
2020
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 |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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
