1. Search for $K^+$ decays into the $\pi^+e^+e^-e^+e^-$ final state
- Author
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Cortina Gil, Eduardo, Minucci, Elisa, Padolski, Sergey, Petrov, Plamen, Velghe, Bob, Bryman, Douglas, Fu, Ji, Numao, Toshio, Petrov, Yevgeniy, Wong, Vincent Wai Sum, Husek, Tomas, Kampf, Karol, Zamkovsky, Michal, Jerhot, Jan, Aliberti, Riccardo, Khoriauli, Gia, Kunze, Jonas, Lomidze, David, Marchevski, Radoslav, Peruzzo, Letizia, Vormstein, Mario, Wanke, Rainer, Cotta Ramusino, Angelo, Dalpiaz, Pietro, Fiorini, Massimiliano, Gamberini, Enrico, Gianoli, Alberto, Neri, Ilaria, Norton, Alan, Petrucci, Ferruccio, Wahl, Heinrich, Bizzeti, Andrea, Bucci, Francesca, Iacopini, Enrico, Latino, Giuseppe, Lenti, Massimo, Parenti, Andrea, Volpe, Roberta, Antonelli, Antonella, Gonnella, Francesco, Lamanna, Gianluca, Lanfranchi, Gaia, Tinti, Gemma, Martellotti, Silvia, Moulson, Matthew, Kozhuharov, Venelin, Litov, Leandar, Georgiev, Georgi, Raggi, Mauro, Spadaro, Tommaso, Ambrosino, Fabio, Fiorenza, Renato, Capussela, Tiziana, Corvino, Michele, Di Filippo, Domenico, Massarotti, Paolo, Mirra, Marco, Napolitano, Marco, Saracino, Giulio, Anzivino, Giuseppina, Imbergamo, Ermanno, Lollini, Riccardo, Santoni, Cristiano, Brizioli, Francesco, Barbanera, Mattia, Cenci, Patrizia, Checcucci, Bruno, Duk, Viacheslav, Lupi, Matteo, Pepe, Monica, Piccini, Mauro, Lubrano, Pasquale, Costantini, Flavio, Doble, Niels, Giorgi, Marcello, Giudici, Sergio, Lari, Enrico, Pinzino, Jacopo, Pontisso, Luca, Sozzi, Marco, Di Lella, Luigi, Mannelli, Italo, Cerri, Claudio, Fantechi, Riccardo, Pedreschi, Elena, Piandani, Roberto, Spinella, Franco, Biagioni, Andrea, d'Agostini, Giulio, Leonardi, Emanuele, Lonardo, Alessandro, Valente, Paolo, Vicini, Piero, Cretaro, Paolo, Turisini, Matteo, Frezza, Ottorino, Ammendola, Roberto, Bonaiuto, Vincenzo, de Simone, Nicola, Federici, Luca, Fucci, Adolfo, Salamon, Andrea, Sargeni, Fausto, Arcidiacono, Roberta, Biino, Cristina, Bloch-Devaux, Brigitte, Boretto, Marco, Filippi, Alessandra, Iacobuzio, Lorenza, Marchetto, Flavio, Menichetti, Ezio, Migliore, Ernesto, Soldi, Dario, Engelfried, Jürgen, Estrada-Tristan, Nora, Bragadireanu, Alexandru Mario, Ghinescu, Stefan Alexandru, Hutanu, Ovidiu Emanuel, Enik, Temur, Falaleev, Valeri, Kekelidze, Vladimir, Korotkova, Anna, Madigozhin, Dmitry, Misheva, Milena, Molokanova, Natalia, Movchan, Sergei, Polenkevich, Irina, Potrebenikov, Yuri, Shkarovskiy, Sergey, Zinchenko, Andrey, Baeva, Aigul, Baigarashev, Dosbol, Emelyanov, Dmitry, Fedotov, Sergei, Khotyantsev, Alexey, Gushchin, Evgeny, Kleimenova, Alina, Kudenko, Yury, Kurochka, Viktoriia, Medvedeva, Mariia, Mefodev, Aleksandr, Shaikhiev, Artur, Kholodenko, Sergey, Kurshetsov, Viktor, Obraztsov, Vladimir, Ostankov, Aleksandr, Semenov, Vitali, Sugonyaev, Valentin, Yushchenko, Oleg, Bician, Lubos, Blazek, Tomas, Cerny, Vladimir, Koval, Michal, Kucerova, Zuzana, Ceccucci, Augusto, Bernhard, Johannes, Danielsson, Hans, Döbrich, Babette, Duval, Francois, Gatignon, Lau, Guida, Roberto, Hahn, Ferdinand, Holzer, Eva Barbara, Jenninger, Berthold, Laycock, Paul, Lehmann Miotto, Giovanna, Lichard, Peter, Mapelli, Alessandro, Noy, Matthew, Palladino, Vito, Perrin-Terrin, Mathieu, Ruggiero, Giuseppe, Ryjov, Vladimir, Schuchmann, Simone, Venditti, Stefano, Brunetti, Maria Brigida, Bache, Thomas, Goudzovski, Evgueni, Henshaw, Jack, Tomczak, Adam, Lazzeroni, Cristina, Fascianelli, Valeria, Lurkin, Nicolas, Newson, Francis, Parkinson, Christopher, Romano, Angela, Sergi, Antonino, Sturgess, Andrew, Swallow, Joel, Heath, Helen, Page, Ryan, Trilov, Stoyan, Angelucci, Bruno, Britton, David, Protopopescu, Dan, Graham, Connor, Jones, Roger William Lewis, Dainton, John Bourke, Fry, John Richard, Fulton, Liam, Hutchcroft, David, Carmignani, Joseph, Massri, Karim, Maurice, Emilie, Wrona, Bozydar, Conovaloff, Adam, Cooper, Peter, Coward, David, Rubin, Philip David, Hives, Zdenko, Akmete, Atakan Tugberk, Soldani, Mattia, Bandiera, Laura, Mazzolari, Andrea, Romagnoni, Marco, Sytov, Alexei, Panichi, Ilaria, Lo Chiatto, Prisco, d'Errico, Mariaelena, Giordano, Raffaele, Briano Olvera, Alejandro, Reyes Santos, Marco Antonio, Boboc, Petre, Kereibay, Dias, Gorshanov, Konstantin, Okhotnikov, Artem, Sadovskiy, Alexander, Sanders, Jack, Kenworthy, Chandler, de Martino, Bianca, Rosa, Ilaria, Ceoletta, Marco, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and NA62
- Subjects
pair production ,CERN Lab ,quantum chromodynamics, axion ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,anomaly ,mediation ,branching ratio ,hidden sector ,NA62 ,Particle Physics - Experiment ,High Energy Physics - Experiment - Abstract
The first search for ultra-rare $K^+$ decays into the $\pi^+e^+e^-e^+e^-$ final state is reported, using a dataset collected by the NA62 experiment at CERN in 2017-2018. An upper limit of $1.4\times 10^{-8}$ at 90% CL is obtained for the branching ratio of the $K^+\to\pi^+e^+e^-e^+e^-$ decay, predicted in the Standard Model to be $(7.2\pm0.7)\times 10^{-11}$. Upper limits at 90% CL are obtained at the level of $10^{-9}$ for the branching ratios of two prompt decay chains involving pair-production of hidden-sector mediators: $K^+\to\pi^+aa$, $a\to e^+e^-$ and $K^+\to\pi^+S$, $S\to A^\prime A^\prime$, $A^\prime\to e^+e^-$. The QCD axion is excluded as a possible explanation of the "17 MeV anomaly"., Comment: Version to be submitted to Physics Letters B
- Published
- 2023