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arXiv · 1803.10303

Observation of $\Upsilon(4S)\to \eta' \Upsilon(1S)$

Belle Collaboration·E. Guido·R. Mussa·U. Tamponi·H. Aihara·S. Al Said·D. M. Asner·H. Atmacan·V. Aulchenko·T. Aushev·R. Ayad·V. Babu·I. Badhrees·A. M. Bakich·V. Bansal·P. Behera·M. Berger·V. Bhardwaj·J. Biswal·A. Bondar·G. Bonvicini·A. Bozek·M. Bračko·T. E. Browder·D. Červenkov·V. Chekelian·A. Chen·B. G. Cheon·K. Chilikin·K. Cho·S. -K. Choi·Y. Choi·S. Choudhury·D. Cinabro·S. Cunliffe·S. Di Carlo·Z. Doležal·S. Eidelman·D. Epifanov·J. E. Fast·T. Ferber·B. G. Fulsom·R. Garg·V. Gaur·N. Gabyshev·A. Garmash·M. Gelb·A. Giri·P. Goldenzweig·J. Haba·T. Hara·H. Hayashii·M. T. Hedges·W. -S. Hou·K. Inami·G. Inguglia·A. Ishikawa·R. Itoh·M. Iwasaki·Y. Iwasaki·W. W. Jacobs·H. B. Jeon·S. Jia·Y. Jin·T. Julius·K. H. Kang·G. Karyan·T. Kawasaki·C. Kiesling·D. Y. Kim·J. B. Kim·K. T. Kim·S. H. Kim·K. Kinoshita·P. Kodyš·S. Korpar·D. Kotchetkov·P. Križan·R. Kroeger·P. Krokovny·R. Kulasiri·R. Kumar·T. Kumita·A. Kuzmin·Y. -J. Kwon·I. S. Lee·S. C. Lee·L. K. Li·Y. B. Li·L. Li Gioi·J. Libby·D. Liventsev·M. Lubej·T. Luo·J. MacNaughton·M. Masuda·T. Matsuda·D. Matvienko·M. Merola·K. Miyabayashi
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Abstract

We report the first observation of the hadronic transition $\Upsilon(4S)\to\eta'\Upsilon(1S)$, using 496 fb$^{-1}$ data collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. We reconstruct the $\eta'$ meson through its decays to $\rho^0\gamma$ and to $\pi^+\pi^-\eta$, with $\eta\to\gamma\gamma$. We measure: ${\cal B}(\Upsilon(4S)\to\eta'\Upsilon(1S))=(3.43\pm 0.88 {\rm(stat.)} \pm 0.21 {\rm(syst.)})\times10^{-5}$, with a significance of 5.7$\sigma$.

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Belle Collaboration, E. Guido, R. Mussa, U. Tamponi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, V. Bansal, P. Behera, M. Berger, V. Bhardwaj, J. Biswal, A. Bondar, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, D. Červenkov, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, K. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Di Carlo, Z. Doležal, S. Eidelman, D. Epifanov, J. E. Fast, T. Ferber, B. G. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Garmash, M. Gelb, A. Giri, P. Goldenzweig, J. Haba, T. Hara, H. Hayashii, M. T. Hedges, W. -S. Hou, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, H. B. Jeon, S. Jia, Y. Jin, T. Julius, K. H. Kang, G. Karyan, T. Kawasaki, C. Kiesling, D. Y. Kim, J. B. Kim, K. T. Kim, S. H. Kim, K. Kinoshita, P. Kodyš, S. Korpar, D. Kotchetkov, P. Križan, R. Kroeger, P. Krokovny, R. Kulasiri, R. Kumar, T. Kumita, A. Kuzmin, Y. -J. Kwon, I. S. Lee, S. C. Lee, L. K. Li, Y. B. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej, T. Luo, J. MacNaughton, M. Masuda, T. Matsuda, D. Matvienko, M. Merola, K. Miyabayashi. 2018-03-27. Observation of $\Upsilon(4S)\to \eta' \Upsilon(1S)$. https://doi.org/10.1103/physrevlett.121.062001

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