E-viri
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Abudinén, F.; Aihara, H.; Aloisio, A.; Ky, N. Anh; Baehr, S.; Bernlochner, F. U.; Bertemes, M.; Biswas, D.; Branchini, P.; Braun, N.; Casarosa, G.; Červenkov, D.; Chen, Y.-T.; Cremaldi, L. M.; De Nuccio, M.; Destefanis, M.; Dey, S.; Dort, K.; Dubey, S.; Eliachevitch, M.; Epifanov, D.; Ganiev, E.; Garmash, A.; Giri, A.; Grace, P.; Hayasaka, K.; Hill, E. C.; Inami, K.; Jabbar, J. Irakkathil; Itoh, R.; Iwasaki, M.; Iwasaki, Y.; Jackson, P.; Kimmel, T. D.; Kohani, S.; Kraetzschmar, T. M. G.; Krokovny, P.; Kumar, J.; Kumar, M.; Kuzmin, A.; Lacaprara, S.; Laurenza, M.; Le Diberder, F. R.; Li, L. K.; Li, S. X.; Longo, S.; Manoni, E.; Marcello, S.; Matsuda, T.; Milesi, M.; Mrvar, M.; Nayak, M.; Nazaryan, G.; Niebuhr, C.; Pakhlov, P.; Paladino, A.; Park, S.-H.; Paschen, B.; Pathak, A.; Patra, S.; Paul, S.; Peruzzi, I.; Piilonen, L. E.; Prell, S.; Prencipe, E.; Prim, M. T.; Rados, P.; Ripp-Baudot, I.; Ritter, M.; Robertson, S. H.; Pérez, D. Rodríguez; Roney, J. M.; Rout, N.; Sahoo, D.; Santelj, L.; Sato, Y.; Schwartz, A. J.; Sobie, R. J.; Sokolov, A.; Spataro, S.; Sumisawa, K.; Sutcliffe, W.; Suzuki, S. Y.; Svidras, H.; Tanida, K.; Tenchini, F.; Uno, K.; Uno, S.; van Tonder, R.; Vitale, L.; Wach, B.; Wang, M.-Z.; Warburton, A.; Watanuki, S.; Wessel, C.; Xu, X. P.; Yook, Y. M.; Yuan, C. Z.; Zani, L.; Zhou, X. Y.
2021Data Set
A search for the flavor-changing neutral-current decay B$^+$→K$^+$$ν\overline{ν}$ is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63 fb$^{-1}$ collected at the $ϒ$(4S) resonance and a sample of 9 fb$^{-1}$ collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B$^+$→K$^+$$ν\overline{ν}$ decay, but also the inclusive properties of the other $B$ meson in the $ϒ$(4S)→$B\overline{B}$ event, to suppress the background from other $B$ meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B$^+$→K$^+$$ν\overline{ν}$ of 4.1×10$^{-5}$ is set at the 90% confidence level.
