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Faculty and Research Publications

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Particle decays

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Articles 1 - 5 of 5

Full-Text Articles in Physics

Search For X(3872) And X(3915) Decay Into Χc1Π0 In B Decays At Belle, The Belle Collaboration, Luminda Kulasiri Jun 2019

Search For X(3872) And X(3915) Decay Into Χc1Π0 In B Decays At Belle, The Belle Collaboration, Luminda Kulasiri

Faculty and Research Publications

We report a search for X(3872) and X (3915) in B+→χc1π0K+ decays. We set an upper limit of B(B+→X(3872)K+)×B(X(3872)→χc1π0)<8.1×10−6 and B(B+→X(3915)K+)×B(X(3915)→χc1π0)<3.8×10−5 at 90% confidence level. We also measure B(X(3872)→χc1π0)/B(X(3872)→J/ψπ+π−)<0.97 at 90% confidence level. The results reported here are obtained from 772×106 B¯B events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider.


Search For C P Violation In The D + → Π + Π 0 Decay At Belle, V. Babu Et Al., D. Joffe, Ratnappuli L. Kulasiri Jan 2018

Search For C P Violation In The D + → Π + Π 0 Decay At Belle, V. Babu Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

We search for CP violation in the charged charm meson decay D+→π+π0, based on a data sample corresponding to an integrated luminosity of 921 fb−1 collected by the Belle experiment at the KEKB e+e− asymmetric-energy collider. The measured CP-violating asymmetry is [+2.31±1.24(stat)±0.23(syst)]%, which is consistent with the standard model prediction and has a significantly improved precision compared to previous results.


Study Of Η And Dipion Transitions In Υ(4 S) Decays To Lower Bottomonia, E. Guido Et Al., D. Joffe, Ratnappuli L. Kulasiri Sep 2017

Study Of Η And Dipion Transitions In Υ(4 S) Decays To Lower Bottomonia, E. Guido Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

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 Aug 2017

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 and Research Publications

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


Search For D^{0} Decays To Invisible Final States At Belle, Y.-T. Lai Et Al., D. Joffe, Ratnappuli L. Kulasiri Nov 2016

Search For D^{0} Decays To Invisible Final States At Belle, Y.-T. Lai Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

We report the result from the first search for D0 decays to invisible final states. The analysis is performed on a data sample of 924  fb−1 collected at and near the Υ(4S) and Υ(5S) resonances with the Belle detector at the KEKB asymmetric-energy e+e− collider. The absolute branching fraction is determined using an inclusive D0 sample, obtained by fully reconstructing the rest of the particle system including the other charmed particle. No significant signal yield is observed and an upper limit of 9.4×10−5 is set on the branching fraction of D0 to invisible final states at 90% confidence level.