% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{CortinaGil:474205, author = {Cortina Gil, Eduardo and Minucci, Elisa and Padolski, Sergey and Petrov, Plamen and Velghe, Bob and Bryman, Douglas and Fu, Ji and Numao, Toshio and Husek, Tomas and Kampf, Karol and Zamkovsky, Michal and Jerhot, Jan and Aliberti, Riccardo and Khoriauli, Gia and Kunze, Jonas and Lomidze, David and Marchevski, Radoslav and Peruzzo, Letizia and Vormstein, Mario and Wanke, Rainer and Cotta Ramusino, Angelo and Dalpiaz, Pietro and Fiorini, Massimiliano and Gamberini, Enrico and Gianoli, Alberto and Neri, Ilaria and Norton, Alan and Petrucci, Ferruccio and Wahl, Heinrich and Bizzeti, Andrea and Bucci, Francesca and Iacopini, Enrico and Latino, Giuseppe and Lenti, Massimo and Parenti, Andrea and Volpe, Roberta and Antonelli, Antonella and Gonnella, Francesco and Lamanna, Gianluca and Lanfranchi, Gaia and Martellotti, Silvia and Moulson, Matthew and Kozhuharov, Venelin and Litov, Leandar and Georgiev, Georgi and Raggi, Mauro and Spadaro, Tommaso and Ambrosino, Fabio and Capussela, Tiziana and Corvino, Michele and Di Filippo, Domenico and Massarotti, Paolo and Mirra, Marco and Napolitano, Marco and Saracino, Giulio and Anzivino, Giuseppina and Imbergamo, Ermanno and Lollini, Riccardo and Santoni, Cristiano and Brizioli, Francesco and Barbanera, Mattia and Cenci, Patrizia and Checcucci, Bruno and Duk, Viacheslav and Lupi, Matteo and Pepe, Monica and Piccini, Mauro and Lubrano, Pasquale and Costantini, Flavio and Doble, Niels and Giorgi, Marcello and Giudici, Sergio and Lari, Enrico and Pinzino, Jacopo and Pontisso, Luca and Sozzi, Marco and Di Lella, Luigi and Mannelli, Italo and Cerri, Claudio and Fantechi, Riccardo and Pedreschi, Elena and Piandani, Roberto and Spinella, Franco and Biagioni, Andrea and D'Agostini, Giulio and Leonardi, Emanuele and Lonardo, Alessandro and Valente, Paolo and Vicini, Piero and Ammendola, Roberto and Bonaiuto, Vincenzo and De Simone, Nicola and Federici, Luca and Fucci, Adolfo and Salamon, Andrea and Sargeni, Fausto and Arcidiacono, Roberta and Biino, Cristina and Bloch-Devaux, Brigitte and Boretto, Marco and Filippi, Alessandra and Iacobuzio, Lorenza and Marchetto, Flavio and Menichetti, Ezio and Migliore, Ernesto and Soldi, Dario and Engelfried, Jürgen and Estrada-Tristan, Nora and Bragadireanu, Alexandru Mario and Ghinescu, Stefan Alexandru and Hutanu, Ovidiu Emanuel and Enik, Temur and Falaleev, Valeri and Kekelidze, Vladimir and Korotkova, Anna and Madigozhin, Dmitry and Misheva, Milena and Molokanova, Natalia and Movchan, Sergei and Polenkevich, Irina and Potrebenikov, Yuri and Shkarovskiy, Sergey and Zinchenko, Alexander and Baeva, Aigul and Baigarashev, Dosbol and Emelyanov, Dmitry and Fedotov, Sergei and Khotyantsev, Alexey and Gushchin, Evgeny and Kleimenova, Alina and Kudenko, Yury and Kurochka, Viktoriia and Medvedeva, Mariia and Mefodev, Aleksandr and Shaikhiev, Artur and Kholodenko, Sergey and Kurshetsov, Viktor and Obraztsov, Vladimir and Ostankov, Aleksandr and Semenov, Vitali and Sugonyaev, Valentin and Yushchenko, Oleg and Bician, Lubos and Blazek, Tomas and Cerny, Vladimir and Koval, Michal and Kucerova, Zuzana and Ceccucci, Augusto and Bernhard, Johannes and Danielsson, Hans and Döbrich, Babette and Duval, Francois and Gatignon, Lau and Guida, Roberto and Hahn, Ferdinand and Holzer, Eva Barbara and Jenninger, Berthold and Laycock, Paul and Lehmann Miotto, Giovanna and Lichard, Peter and Mapelli, Alessandro and Noy, Matthew and Palladino, Vito and Perrin-Terrin, Mathieu and Ruggiero, Giuseppe and Ryjov, Vladimir and Schuchmann, Simone and Venditti, Stefano and Brunetti, Maria Brigida and Bache, Thomas and Goudzovski, Evgueni and Lazzeroni, Cristina and Fascianelli, Valeria and Lurkin, Nicolas and Newson, Francis and Parkinson, Christopher and Romano, Angela and Sergi, Antonino and Sturgess, Andrew and Swallow, Joel and Heath, Helen and Page, Ryan and Trilov, Stoyan and Angelucci, Bruno and Britton, David and Protopopescu, Dan and Graham, Connor and Jones, Roger William Lewis and Dainton, John Bourke and Fry, John Richard and Fulton, Liam and Hutchcroft, David and Carmignani, Joseph and Massri, Karim and Maurice, Emilie and Wrona, Bozydar and Conovaloff, Adam and Cooper, Peter and Coward, David and Rubin, Philip David}, collaboration = {{NA62 Collaboration}}, title = {{S}earch for $\pi^0$ decays to invisible particles}, journal = {Journal of high energy physics}, volume = {02}, number = {2}, issn = {1029-8479}, address = {[Trieste]}, publisher = {SISSA}, reportid = {PUBDB-2022-00595, arXiv:2010.07644. CERN-EP-2020-193}, pages = {201}, year = {2021}, abstract = {The NA62 experiment at the CERN SPS reports a study of a sample of $4 \times10^{9}$ tagged $\pi^0$ mesons from $K^+ \to \pi^+ \pi^0 (\gamma)$, searching for the decay of the $\pi^0$ to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of $4.4 \times10^{-9}$ is set on the branching ratio at 90\% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model-independent upper limit on the branching ratio for the decay $K^+ \to \pi^+ X$, where $X$ is a particle escaping detection with mass in the range 0.110-0.155 GeV$/c^2$ and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming $X$ to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.}, keywords = {pi0: invisible decay (INSPIRE) / background: fluctuation (INSPIRE) / fermion: coupling (INSPIRE) / pi0: branching ratio: upper limit (INSPIRE) / K: branching ratio (INSPIRE) / axion-like particles (INSPIRE) / hidden sector (INSPIRE) / CERN SPS (INSPIRE) / lifetime (INSPIRE) / mixing (INSPIRE) / NA62 (INSPIRE) / experimental results (INSPIRE)}, cin = {$Z_EL$}, ddc = {530}, cid = {$I:(DE-H253)Z_EL-20210408$}, pnm = {611 - Fundamental Particles and Forces (POF4-611)}, pid = {G:(DE-HGF)POF4-611}, experiment = {EXP:(DE-MLZ)NOSPEC-20140101}, typ = {PUB:(DE-HGF)16}, eprint = {2010.07644}, howpublished = {arXiv:2010.07644}, archivePrefix = {arXiv}, SLACcitation = {$\%\%CITATION$ = $arXiv:2010.07644;\%\%$}, UT = {WOS:000681463700001}, doi = {10.1007/JHEP02(2021)201}, url = {https://bib-pubdb1.desy.de/record/474205}, }