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新山 雅之 所属 京都産業大学 理学部 物理科学科 職種 教授 |
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| 発行・発表の年月 | 2017/07 |
| 形態種別 | その他 |
| 標題 | Study of $η$ and dipion transitions in $Υ(4S)$ decays to lower bottomonia |
| 執筆形態 | その他 |
| 著者・共著者 | 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. |
| 概要 | 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. |
| DOI | 10.1103/PhysRevD.96.052005 |
| PermalinkURL | http://arxiv.org/abs/1707.04973v2 |
| researchmap用URL | http://arxiv.org/pdf/1707.04973v2 |