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arXiv · 1707.04973

Study of $\eta$ and dipion transitions in $\Upsilon(4S)$ decays to lower bottomonia

Belle Collaboration·E. Guido·R. Mussa·U. Tamponi·I. Adachi·H. Aihara·S. Al Said·D. M. Asner·V. Aulchenko·T. Aushev·R. Ayad·I. Badhrees·A. M. Bakich·V. Bansal·P. Behera·V. Bhardwaj·B. Bhuyan·J. Biswal·A. Bobrov·A. Bondar·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·D. Cinabro·N. Dash·S. Di Carlo·Z. Doležal·Z. Drásal·S. Eidelman·D. Epifanov·H. Farhat·J. E. Fast·T. Ferber·B. G. Fulsom·V. Gaur·N. Gabyshev·A. Garmash·M. Gelb·R. Gillard·P. Goldenzweig·J. Haba·T. Hara·K. Hayasaka·H. Hayashii·M. T. Hedges·W. -S. Hou·T. Iijima·K. Inami·G. Inguglia·A. Ishikawa·R. Itoh·Y. Iwasaki·W. W. Jacobs·I. Jaegle·H. B. Jeon·S. Jia·Y. Jin·D. Joffe·K. K. Joo·T. Julius·K. H. Kang·G. Karyan·T. Kawasaki·D. Y. Kim·J. B. Kim·K. T. Kim·M. J. Kim·S. H. Kim·Y. J. Kim·K. Kinoshita·P. Kodyš·S. Korpar·D. Kotchetkov·P. Križan·P. Krokovny·R. Kulasiri·T. Kumita·A. Kuzmin·Y. -J. Kwon·J. S. Lange·P. Lewis·C. H. Li·L. Li·L. Li Gioi·J. Libby·D. Liventsev·M. Lubej·T. Luo·M. Masuda·T. Matsuda·D. Matvienko·M. Merola
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Abstract

We study hadronic transitions between bottomonium states using 496 fb$^{-1}$ data collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^{+}e^{-}$ collider. We measure: ${\cal B}(\Upsilon(4S)\to\pi^+\pi^-\Upsilon(1S))=(8.2\pm 0.5 {\rm(stat.)} \pm 0.4 {\rm(syst.)})\times10^{-5}$, ${\cal B}(\Upsilon(4S)\to\pi^+\pi^-\Upsilon(2S))=(7.9\pm 1.0 {\rm(stat.)} \pm 0.4 {\rm(syst.)})\times10^{-5}$, and ${\cal B}(\Upsilon(4S)\to\eta\Upsilon(1S))=(1.70\pm 0.23 {\rm(stat.)} \pm 0.08 {\rm(syst.)})\times10^{-4}$. We measure the ratio of branching fractions ${\cal R} = {\cal B}(\Upsilon(4S)\to\eta\Upsilon(1S))/{\cal B}(\Upsilon(4S)\to\pi^+\pi^-\Upsilon(1S)) = 2.07\pm 0.30 {\rm(stat.)} \pm 0.11 {\rm(syst.)}$. We search for the decay $\Upsilon(1^3D_{1,2})\to\eta\Upsilon(1S)$, but do not find significant evidence for such a transition. We also measure the initial state radiation production cross sections of the $\Upsilon(2S,3S)$ resonances and we find values compatible with the expected ones. Finally, the analysis of the $\Upsilon(4S)\to\pi^+\pi^-\Upsilon(1S)$ events shows indications for a resonant contribution due to the $f_0(980)$ meson.

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Belle Collaboration, E. Guido, R. Mussa, U. Tamponi, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, I. Badhrees, A. M. Bakich, V. Bansal, P. Behera, V. Bhardwaj, B. Bhuyan, J. Biswal, A. Bobrov, A. Bondar, 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, D. Cinabro, N. Dash, S. Di Carlo, Z. Doležal, Z. Drásal, S. Eidelman, D. Epifanov, H. Farhat, J. E. Fast, T. Ferber, B. G. Fulsom, V. Gaur, N. Gabyshev, A. Garmash, M. Gelb, R. Gillard, P. Goldenzweig, J. Haba, T. Hara, K. Hayasaka, H. Hayashii, M. T. Hedges, W. -S. Hou, T. Iijima, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, Y. Iwasaki, W. W. Jacobs, I. Jaegle, H. B. Jeon, S. Jia, Y. Jin, D. Joffe, K. K. Joo, T. Julius, K. H. Kang, G. Karyan, T. Kawasaki, D. Y. Kim, J. B. Kim, K. T. Kim, M. J. Kim, S. H. Kim, Y. J. Kim, K. Kinoshita, P. Kodyš, S. Korpar, D. Kotchetkov, P. Križan, P. Krokovny, R. Kulasiri, T. Kumita, A. Kuzmin, Y. -J. Kwon, J. S. Lange, P. Lewis, C. H. Li, L. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej, T. Luo, M. Masuda, T. Matsuda, D. Matvienko, M. Merola. 2017-07-17. Study of $\eta$ and dipion transitions in $\Upsilon(4S)$ decays to lower bottomonia. https://doi.org/10.1103/physrevd.96.052005

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