Search for K<sup>+</sup> decays to a lepton and invisible particles

Volpe, R, Akmete, A, Aliberti, R, Ambrosino, F, Ammendola, R, Angelucci, B, Antonelli, A, Anzivino, G, Arcidiacono, R, Bache, T
et al (show 90 more authors) (2021) Search for K<sup>+</sup> decays to a lepton and invisible particles. .

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The NA62 experiment at CERN reports searches for K+ → e+N, K+ → µ+N and K+ → µ+X decays, where N and X are massive invisible particles, using the 2016-2018 data set. The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of O(10−9) and O(10−8) on the neutrino mixing parameter |Ue4|2 and |Uµ4|2, improving on the earlier searches for heavy neutral lepton production and decays in the kinematically accessible mass range. The X particle is considered a scalar or vector hidden sector mediator decaying to an invisible final state, and upper limits of the decay branching fraction for X masses in the range 10-370 MeV/c2 are reported for the first time, ranging from O(10−5) to O(10−7). An upper limit of 1.0 · 10−6 is established at 90% CL on the K+ → µ+ννν¯ branching fraction.

Item Type: Conference or Workshop Item (Unspecified)
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 14 Mar 2023 15:55
Last Modified: 14 Mar 2023 15:55
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