1. Search for heavy neutral lepton production in K+ decays to positrons
- Author
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Fabrizio Petrucci, F. Hahn, B. Jenninger, Mario Giorgi, D. Di Filippo, Leander Litov, P. Rubin, S. Padolski, Paul Laycock, Evgueni Goudzovski, S. Martellotti, Claudio Santoni, A. Filippi, G. Saracino, M. Vormstein, D. Emelyanov, B. Angelucci, L. Iacobuzio, E. B. Holzer, A. I. Zinchenko, M. Koval, Mattia Barbanera, G. Latino, M. Medvedeva, Giuseppe Ruggiero, V. Palladino, Yu. Potrebenikov, L. Bician, A. Fucci, Tommaso Spadaro, J. Swallow, Y. Petrov, Johannes Bernhard, A. Parenti, F. Spinella, H. D. Wahl, D. Coward, E. Iacopini, R. Lollini, T. Capussela, A. Gianoli, Roberto Guida, J. L. Fu, G. Lanfranchi, J. R. Fry, G. Lamanna, Ernesto Migliore, Tomáš Husek, Georgi P. Georgiev, Viacheslav Duk, T. Bache, R. W. L. Jones, A. Kleimenova, F. Costantini, Alessandro Lonardo, E. Cortina Gil, Roberto Piandani, G. Anzivino, L. Peruzzo, Andrea Biagioni, R. Volpe, L. Gatignon, M. Fiorini, M. Corvino, M. Piccini, P. F. Dalpiaz, R. Marchevski, E. Gamberini, D. T. Madigozhin, J. Jerhot, Roberto Ammendola, L. Di Lella, R. Page, V. Kozhuharov, N. A. Molokanova, A. Conovaloff, M. Misheva, M. Zamkovsky, S. Movchan, C. Lazzeroni, F. Ambrosino, D. Protopopescu, B. Velghe, J. Carmignani, A. Salamon, G. Khoriauli, R. Fantechi, Nicolas Lurkin, Matteo Lupi, F. Brizioli, A. Mefodev, M. B. Brunetti, Paolo Massarotti, M. Napolitano, B. Bloch-Devaux, V. Kurochka, Helen F Heath, I. Mannelli, Jürgen Engelfried, B. Wrona, A. Korotkova, A. Sturgess, J. B. Dainton, E. Lari, V. Cerny, H. O. Danielsson, C. Cerri, S. Trilov, Jacopo Pinzino, M. Perrin-Terrin, Vladimir Kekelidze, Luca Pontisso, Antonino Sergi, S. Schuchmann, Emilio Leonardi, A. M. Bragadireanu, I. Polenkevich, L. Federici, S. Venditti, E. Imbergamo, M. Moulson, N. Doble, A. Baeva, D. Baigarashev, Karol Kampf, V. Obraztsov, S. Ghinescu, T. Numao, Paolo Valente, Mauro Raggi, E. Pedreschi, E. Menichetti, V. E. Semenov, A. Shaikhiev, Francesco Gonnella, Rainer Wanke, M. Mirra, Tomas Blazek, Dave Britton, N. Estrada-Tristan, A. Cotta Ramusino, Yu.A. Kudenko, A. Ceccucci, Andrea Bizzeti, G. Lehmann Miotto, C. Graham, Roberta Arcidiacono, P. Petrov, Z. Kucerova, E. Gushchin, A. Khotyantsev, M. Lenti, F. Bucci, M. Boretto, V. Falaleev, F. Newson, P. Cenci, Babette Döbrich, S. Shkarovskiy, C. J. Parkinson, E. Minucci, V. Fascianelli, A. Antonelli, D. Soldi, V. Sugonyaev, R. Aliberti, A. Norton, K. Massri, J. Kunze, D. Lomidze, D. E. Hutchcroft, O. Yushchenko, V. Kurshetsov, S. Kholodenko, L. Fulton, B. Checcucci, F. Duval, P. Cooper, M. Sozzi, Ilaria Neri, Vincenzo Bonaiuto, T. Enik, Douglas Bryman, Sergei Fedotov, Vladimir Ryjov, A. Mapelli, S. Giudici, Cristina Biino, A. Romano, Fausto Sargeni, A P Ostankov, J. Henshaw, Matthew Noy, E. Maurice, F. Marchetto, Piero Vicini, P. Lichard, G. D'Agostini, M. Pepe, O. Hutanu, P. Lubrano, N. De Simone, Ambrosino, F., Corvino, M., Massarotti, P., Mirra, M., Napolitano, M., Saracino, G., 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 UCL - SST/IRMP - Institut de recherche en mathématique et physique
- Subjects
Astrofísica ,Nuclear and High Energy Physics ,Heavy neutral lepton, kaon meson, kaon decay, positron ,Pontecorvo–Maki–Nakagawa–Sakata matrix ,Socio-culturale ,FOS: Physical sciences ,NA62 experiment ,7. Clean energy ,01 natural sciences ,NA62 ,High Energy Physics - Experiment ,Nuclear physics ,High Energy Physics - Experiment (hep-ex) ,Positron ,kaon decays, heavy neutral lepton, SM extensions ,PE2_2 ,Big Bang nucleosynthesis ,SM extensions ,kaon physics ,0103 physical sciences ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,010306 general physics ,ComputingMilieux_MISCELLANEOUS ,Physics ,Range (particle radiation) ,Large Hadron Collider ,kaon decays ,010308 nuclear & particles physics ,hep-ex ,Settore FIS/04 ,Heavy neutral lepton ,lepton flavour violation ,Física ,lcsh:QC1-999 ,kaon meson ,kaon decay ,positron ,Production (computer science) ,High Energy Physics::Experiment ,kaon ,lcsh:Physics ,Particle Physics - Experiment ,Lepton - Abstract
A search for heavy neutral lepton ($N$) production in $K^+\to e^+N$ 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 $|U_{e4}|^2$ are established at the level of $10^{-9}$ over most of the accessible heavy neutral lepton mass range 144--462 MeV/$c^2$, with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The $|U_{e4}|^2$ range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/$c^2$., Comment: Version accepted for publication in Physics Letters B (28 June 2020)