Search for heavy neutral lepton production in K+ decays to positrons



Cortina Gil, E, Kleimenova, A, Minucci, E, Padolski, S, Petrov, P, Shaikhiev, A, Volpe, R, Numao, T, Petrov, Y, Velghe, B
et al (show 192 more authors) (2020) Search for heavy neutral lepton production in K+ decays to positrons. Physics Letters B, 807. p. 135599. ISSN 0370-2693, 1873-2445

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Abstract

A search for heavy neutral lepton (N) production in K<sup>+</sup>→e<sup>+</sup>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 |U<inf>e4</inf>|<sup>2</sup> are established at the level of 10<sup>−9</sup> over most of the accessible heavy neutral lepton mass range 144–462 MeV/c<sup>2</sup>, with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The |U<inf>e4</inf>|<sup>2</sup> range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/c<sup>2</sup>.

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 17 Jul 2020 07:57
Last Modified: 10 Jun 2025 07:00
DOI: 10.1016/j.physletb.2020.135599
Related Websites:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3094255