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arXiv · 2110.14086

Search for $B^0$ meson decays into $\Lambda$ and missing energy with a hadronic tagging method at Belle

Belle Collaboration·C. Hadjivasiliou·B. G. Fulsom·J. F. Strube·I. Adachi·H. Aihara·D. M. Asner·H. Atmacan·T. Aushev·V. Babu·K. Belous·J. Bennett·M. Bessner·V. Bhardwaj·B. Bhuyan·T. Bilka·J. Biswal·D. Bodrov·J. Borah·A. Bozek·M. Bračko·P. Branchini·T. E. Browder·A. Budano·M. Campajola·D. Červenkov·M. -C. Chang·P. Chang·A. Chen·B. G. Cheon·K. Chilikin·H. E. Cho·S. -K. Choi·Y. Choi·S. Choudhury·D. Cinabro·S. Cunliffe·S. Das·G. De Pietro·F. Di Capua·Z. Doležal·T. V. Dong·D. Dossett·D. Epifanov·T. Ferber·R. Garg·V. Gaur·A. Giri·P. Goldenzweig·T. Gu·K. Gudkova·H. Hayashii·W. -S. Hou·C. -L. Hsu·T. Iijima·K. Inami·G. Inguglia·A. Ishikawa·M. Iwasaki·Y. Iwasaki·W. W. Jacobs·S. Jia·Y. Jin·J. Kahn·A. B. Kaliyar·K. H. Kang·G. Karyan·C. Kiesling·C. H. Kim·D. Y. Kim·K. T. Kim·Y. -K. Kim·P. Kodyš·T. Konno·A. Korobov·S. Korpar·E. Kovalenko·P. Križan·R. Kroeger·P. Krokovny·R. Kumar·K. Kumara·Y. -J. Kwon·S. C. Lee·L. K. Li·S. X. Li·Y. B. Li·L. Li Gioi·J. Libby·K. Lieret·C. MacQueen·M. Masuda·D. Matvienko·M. Merola·K. Miyabayashi·R. Mizuk·G. B. Mohanty·R. Mussa·M. Nakao·Z. Natkaniec
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Abstract

We present a search for the decays of $B^0$ mesons into a final state containing a $\Lambda$ baryon and missing energy. These results are obtained from a $711\text{fb}^{-1}$ data sample that contains $772 \times 10^6$ $B{\kern 0.18em}\overline{\kern -0.18em B}$ pairs and was collected near the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We use events in which one $B$ meson is fully reconstructed in a hadronic decay mode and require the remainder of the event to consist of only a single $\Lambda$. No evidence for these decays is found and we set $90\%$ confidence level upper limits on the branching fractions in the range $2.1$-$3.8\times 10^{-5}$. This measurement provides the world's most restrictive limits, with implications for baryogenesis and dark matter production.

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Belle Collaboration, C. Hadjivasiliou, B. G. Fulsom, J. F. Strube, I. Adachi, H. Aihara, D. M. Asner, H. Atmacan, T. Aushev, V. Babu, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, D. Bodrov, J. Borah, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. Červenkov, M. -C. Chang, P. Chang, A. Chen, B. G. Cheon, K. Chilikin, H. E. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Das, G. De Pietro, F. Di Capua, Z. Doležal, T. V. Dong, D. Dossett, D. Epifanov, T. Ferber, R. Garg, V. Gaur, A. Giri, P. Goldenzweig, T. Gu, K. Gudkova, H. Hayashii, W. -S. Hou, C. -L. Hsu, T. Iijima, K. Inami, G. Inguglia, A. Ishikawa, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, S. Jia, Y. Jin, J. Kahn, A. B. Kaliyar, K. H. Kang, G. Karyan, C. Kiesling, C. H. Kim, D. Y. Kim, K. T. Kim, Y. -K. Kim, P. Kodyš, T. Konno, A. Korobov, S. Korpar, E. Kovalenko, P. Križan, R. Kroeger, P. Krokovny, R. Kumar, K. Kumara, Y. -J. Kwon, S. C. Lee, L. K. Li, S. X. Li, Y. B. Li, L. Li Gioi, J. Libby, K. Lieret, C. MacQueen, M. Masuda, D. Matvienko, M. Merola, K. Miyabayashi, R. Mizuk, G. B. Mohanty, R. Mussa, M. Nakao, Z. Natkaniec. 2021-10-26. Search for $B^0$ meson decays into $\Lambda$ and missing energy with a hadronic tagging method at Belle. https://doi.org/10.1103/physrevd.105.l051101

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