An investigation of the very rare K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ decay

Abstract The NA62 experiment reports an investigation of the K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ mode from a sample of K + decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of (0.389 ± 0.024) × 10 −10, corresponding to 2.2 event...

Full description

Bibliographic Details
Main Authors: The NA62 collaboration, E. Cortina Gil, A. Kleimenova, E. Minucci, S. Padolski, P. Petrov, A. Shaikhiev, R. Volpe, T. Numao, B. Velghe, D. Bryman, J. Fu, T. Husek, J. Jerhot, K. Kampf, M. Zamkovsky, R. Aliberti, G. Khoriauli, J. Kunze, D. Lomidze, R. Marchevski, L. Peruzzo, M. Vormstein, R. Wanke, P. Dalpiaz, M. Fiorini, I. Neri, A. Norton, F. Petrucci, H. Wahl, A. Cotta Ramusino, A. Gianoli, E. Iacopini, G. Latino, M. Lenti, A. Parenti, A. Bizzeti, F. Bucci, A. Antonelli, G. Georgiev, V. Kozhuharov, G. Lanfranchi, S. Martellotti, M. Moulson, T. Spadaro, F. Ambrosino, T. Capussela, M. Corvino, D. Di Filippo, P. Massarotti, M. Mirra, M. Napolitano, G. Saracino, G. Anzivino, F. Brizioli, E. Imbergamo, R. Lollini, R. Piandani, C. Santoni, M. Barbanera, P. Cenci, B. Checcucci, P. Lubrano, M. Lupi, M. Pepe, M. Piccini, F. Costantini, L. Di Lella, N. Doble, M. Giorgi, S. Giudici, G. Lamanna, E. Lari, E. Pedreschi, M. Sozzi, C. Cerri, R. Fantechi, L. Pontisso, F. Spinella, I. Mannelli, G. D’Agostini, M. Raggi, A. Biagioni, E. Leonardi, A. Lonardo, P. Valente, P. Vicini, R. Ammendola, V. Bonaiuto, A. Fucci, A. Salamon, F. Sargeni, R. Arcidiacono, B. Bloch-Devaux, M. Boretto, E. Menichetti, E. Migliore, D. Soldi, C. Biino, A. Filippi, F. Marchetto, J. Engelfried, N. Estrada-Tristan, A. M. Bragadireanu, S. A. Ghinescu, O. E. Hutanu, A. Baeva, D. Baigarashev, D. Emelyanov, T. Enik, V. Falaleev, V. Kekelidze, A. Korotkova, L. Litov, D. Madigozhin, M. Misheva, N. Molokanova, S. Movchan, I. Polenkevich, Yu. Potrebenikov, S. Shkarovskiy, A. Zinchenko, S. Fedotov, E. Gushchin, A. Khotyantsev, Y. Kudenko, V. Kurochka, M. Medvedeva, A. Mefodev, S. Kholodenko, V. Kurshetsov, V. Obraztsov, A. Ostankov, V. Semenov, V. Sugonyaev, O. Yushchenko, L. Bician, T. Blazek, V. Cerny, Z. Kucerova, J. Bernhard, A. Ceccucci, H. Danielsson, N. De Simone, F. Duval, B. Döbrich, L. Federici, E. Gamberini, L. Gatignon, R. Guida, F. Hahn, E. B. Holzer, B. Jenninger, M. Koval, P. Laycock, G. Lehmann Miotto, P. Lichard, A. Mapelli, K. Massri, M. Noy, V. Palladino, M. Perrin-Terrin, J. Pinzino, V. Ryjov, S. Schuchmann, S. Venditti, T. Bache, M. B. Brunetti, V. Duk, V. Fascianelli, J. R. Fry, F. Gonnella, E. Goudzovski, L. Iacobuzio, C. Lazzeroni, N. Lurkin, F. Newson, C. Parkinson, A. Romano, A. Sergi, A. Sturgess, J. Swallow, H. Heath, R. Page, S. Trilov, B. Angelucci, D. Britton, C. Graham, D. Protopopescu, J. Carmignani, J. B. Dainton, R. W. L. Jones, G. Ruggiero, L. Fulton, D. Hutchcroft, E. Maurice, B. Wrona, A. Conovaloff, P. Cooper, D. Coward, P. Rubin
Format: Article
Language:English
Published: SpringerOpen 2020-11-01
Series:Journal of High Energy Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/JHEP11(2020)042
Description
Summary:Abstract The NA62 experiment reports an investigation of the K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ mode from a sample of K + decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of (0.389 ± 0.024) × 10 −10, corresponding to 2.2 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10 −11. Two signal candidates are observed with an expected background of 1.5 events. Combined with the result of a similar analysis conducted by NA62 on a smaller data set recorded in 2016, the collaboration now reports an upper limit of 1.78 × 10 −10 for the K + → π + ν ν ¯ $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ branching ratio at 90% CL. This, together with the corresponding 68% CL measurement of ( 0.48 − 0.48 + 0.72 $$ {0.48}_{-0.48}^{+0.72} $$ ) × 10 −10, are currently the most precise results worldwide, and are able to constrain some New Physics models that predict large enhancements still allowed by previous measurements.
ISSN:1029-8479