Search for K⁺ decays to a lepton and invisible particles

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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) , Baeva, A, Baigarashev, D, Bandiera, L, Barbanera, M, Bernhard, J, Biagioni, A, Bician, L, Biino, C, Bizzeti, A, Blazek, T, Bloch-Devaux, B, Boboc, P, Bonaiuto, V, Boretto, M, Bragadireanu, M, Olvera, AB, Britton, D, Brizioli, F, Brunetti, MB, Bryman, D, Bucci, F, Capussela, T, Carmignani, J, Ceccucci, A, Cenci, P, Cerny, V, Cerri, C, Checcucci, B, Conovaloff, A, Cooper, P, Gil, EC, Corvino, M, Costantini, F, Ramusino, AC, Coward, D, Cretaro, P, D'Agostini, G, Dainton, J, Dalpiaz, P, Danielsson, H, D'Errico, M, De Simone, N, Di Filippo, D, Di Lella, L, Doble, N, Dobrich, B, Duval, F, Duk, V, Emelyanov, D, Engelfried, J, Enik, T, Estrada-Tristan, N, Falaleev, V, Fantechi, R, Fascianelli, V, Federici, L, Fedotov, S, Filippi, A, Fiorenza, R, Fiorini, M, Frezza, O, Fry, J, Fu, J, Fucci, A, Fulton, L, Gamberini, E, Gatignon, L, Georgiev, G, Ghinescu, S, Gianoli, A, Giorgi, M, Giudici, S, Gonnella, F, Gorshanov, K, Goudzovski, E, Graham, C, Guida, R, Gushchin, E, Hahn, F, Heath, H, Henshaw, J, Hives, Z, Holzer, EB, Husek, T, Hutanu, O, Hutchcroft, D ORCID: 0000-0002-4174-6509, Iacobuzio, L, Iacopini, E, Imbergamo, E and Jenninger, B (2021) Search for K⁺ decays to a lepton and invisible particles. .

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Abstract

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
Open Access URL:	https://pos.sissa.it/402/157/
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3169067