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Study of η and dipion transitions in Υ ( 4S ) decays to lower bottomonia
Here, we study hadronic transitions between bottomonium states using 496fb-1 data collected at the Υ ( 4S ) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. We measure B ( Υ ( 4S ) → π+π- Υ ( 1S ) ) = ( 8.2±0.5 ( stat ) ±0.4 ( syst ) ) ×10-5 , B ( Υ ( 4S ) → π+π- Υ ( 2S...
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Published in: | Physical review. D 2017-09, Vol.96 (5) |
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Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
Format: | Article |
Language: | English |
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Online Access: | Get full text |
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Summary: | Here, we study hadronic transitions between bottomonium states using 496fb-1 data collected at the Υ ( 4S ) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. We measure B ( Υ ( 4S ) → π+π- Υ ( 1S ) ) = ( 8.2±0.5 ( stat ) ±0.4 ( syst ) ) ×10-5 , B ( Υ ( 4S ) → π+π- Υ ( 2S ) ) = ( 7.9±1.0 ( stat ) ± 0.4 ( syst ) ) ×10-5 , and B ( Υ ( 4S ) → η Υ ( 1S ) ) = ( 1.70±0.23 ( stat ) ±0.08 ( syst ) ) ×10-4 . We measure the ratio of branching fractions R = B ( Υ ( 4S ) → η Υ ( 1S ) ) / B ( Υ ( 4S ) → π+π- Υ ( 1S ) ) =2.07±0.30 ( stat ) ± 0.11 ( syst ) . We search for the decay Υ ( 1D31,2 ) → η Υ ( 1S ) , but do not find significant evidence for such a transition. We also measure the initial-state radiation production cross sections of the Υ ( 2S,3S ) resonances and we find values compatible with the expected ones. Finally, the analysis of the Υ ( 4S ) → π+π- Υ ( 1S ) events reflects indications for a resonant contribution due to the f0 ( 980 ) meson. |
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ISSN: | 2470-0010 |