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Study Of Η And Dipion Transitions In Υ(4 S) Decays To Lower Bottomonia, E. Guido Et Al., D. Joffe, Ratnappuli L. Kulasiri
Study Of Η And Dipion Transitions In Υ(4 S) Decays To Lower Bottomonia, E. Guido Et Al., D. Joffe, Ratnappuli L. Kulasiri
Faculty Articles
We study hadronic transitions between bottomonium states using 496 fb−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)→ηΥ(1S))=(1.70±0.23(stat)±0.08(syst))×10−4. We measure the ratio of branching fractions R=B(Υ(4S)→ηΥ(1S))/B(Υ(4S)→π+π−Υ(1S))=2.07±0.30(stat)±0.11(syst). We search for the decay Υ(13D1,2)→ηΥ(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 shows indications for a resonant contribution due to the f0(980) meson.
Measurement Of The Branching Fraction And Cp Asymmetry In B 0 → Π 0Π 0 Decays, And An Improved Constraint On Φ2, T. Julius Et Al., D. Joffe, Ratnappuli L. Kulasiri
Measurement Of The Branching Fraction And Cp Asymmetry In B 0 → Π 0Π 0 Decays, And An Improved Constraint On Φ2, T. Julius Et Al., D. Joffe, Ratnappuli L. Kulasiri
Faculty Articles
We measure the branching fraction and CP violation asymmetry in the decay B0→π0π0, using a data sample of 752×106 B¯B pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB e+e− collider. The obtained branching fraction and direct CP asymmetry are B(B→π0π0)=[1.31±0.19(stat)±0.19(syst)]×10−6 and ACP=+0.14±0.36(stat)±0.10(syst), respectively. The signal significance, including the systematic uncertainty, is 6.4 standard deviations. We combine these results with Belle’s earlier measurements of B0→π+π− and B±→π±π0 to exclude the CP-violating parameter ϕ2 from the range 15.5°<ϕ2