1. Search for K+ decays to a lepton and invisible particles
- Author
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Volpe, Roberta, Akmete, A, Aliberti, R, Ambrosino, F, Ammendola, R, Angelucci, B, Antonelli, A, Anzivino, G, Arcidiacono, R, Bache, T, 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, A Briano, Britton, D, Brizioli, F, Brunetti, M B, Bryman, D, Bucci, F, Capussela, T, Carmignani, J, Ceccucci, A, Cenci, P, Cerny, V, Cerri, C, Checcucci, B, Conovaloff, A, Cooper, P, Cortina Gil, E, Corvino, M, Costantini, F, Cotta Ramusino, A, 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, E B, Husek, T, Hutanu, O, Hutchcroft, D, Iacobuzio, L, Iacopini, E, Imbergamo, E, Jenninger, B, Jerhot, J, Jones, R W, Kampf, K, Kekelidze, V, Kereibay, D, Kholodenko, S, Khoriauli, G, Khotyantsev, A, Kleimenova, A, Korotkova, A, Koval, M, Kozhuharov, V, Kucerova, Z, Kudenko, Y, Kunze, J, Kurochka, V, Kurshetsov, V, Lanfranchi, G, Lamanna, G, Lari, E, Latino, G, Laycock, P, Lazzeroni, C, Lenti, M, Lehmann Miotto, G, Leonardi, E, Lichard, P, Litov, L, Chiatto, P Lo, Lollini, R, Lomidze, D, Lonardo, A, Lubrano, P, Lupi, M, Lurkin, N, Madigozhin, D, Mannelli, I, Mapelli, A, Marchetto, F, Marchevski, R, Martellotti, S, Massarotti, P, Massri, K, Maurice, E, Mazzolari, A, Medvedeva, M, Mefodev, A, Menichetti, E, Migliore, E, Minucci, E, Mirra, M, Misheva, M, Molokanova, N, Moulson, M, Movchan, S, Napolitano, M, Neri, I, Newson, F, Norton, A, Noy, M, Numao, T, Obraztsov, V, Okhotnikov, A, Ostankov, A, Padolski, S, Page, R, Palladino, V, Panichi, I, Parenti, A, Parkinson, C, Pedreschi, E, Pepe, M, Perrin-Terrin, M, Peruzzo, L, Petrov, P, Petrov, Y, Petrucci, F, Piandani, R, Piccini, M, Pinzino, J, Polenkevich, I, Pontisso, L, Potrebenikov, Yu, Protopopescu, D, Raggi, M, Santos, M Reyes, Romagnoni, M, Romano, A, Rubin, P, Ruggiero, G, Ryjov, V, Sadovsky, A, Salamon, A, Santoni, C, Saracino, G, Sargeni, F, Schuchmann, S, Semenov, V, Sergi, A, Shaikhiev, A, Shkarovskiy, S, Soldani, M, Soldi, D, Sozzi, M, Spadaro, T, Spinella, F, Sturgess, A, Sugonyaev, V, Swallow, J, Sytov, A, Tinti, G, Tomczak, A, Trilov, S, Turisini, M, Valente, P, Velghe, B, Venditti, S, Vicini, P, Volpe, R, Vormstein, M, Wahl, H, Wanke, R, Wong, V, Wrona, B, Yushchenko, O, Zamkovsky, M, and Zinchenko, A
- Subjects
kaon decays ,Settore FIS/04 ,heavy neutral leptons ,Nuclear Physics - Experiment ,Particle Physics - Experiment ,kaon decays, heavy neutral leptons - Abstract
The NA62 experiment at CERN reports searches for $K^+ \to e^+ N$, $K^+ \to \mu^+ N$ and $K^+ \to \mu^+ X$ 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 $|U_{e4}|^2$ and $|U_{\mu 4}|^2$, 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/c$^2$ are reported for the first time, ranging from $O(10^{-5})$ to $O(10^{-7})$. An upper limit of $1.0 \cdot 10^{-6}$ is established at 90\% CL on the $K^+\to \mu^+ \nu \nu \bar{\nu}$ branching fraction.
- Published
- 2022