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Faculty and Research Publications

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Rare decays

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Articles 1 - 6 of 6

Full-Text Articles in Physics

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


Measurement Of Branching Fraction And Direct Cp Asymmetry In Charmless B+ → K+K−Π + Decays At Belle, C.-L. Hsu Et Al., D. Joffe, Ratnappuli L. Kulasiri Aug 2017

Measurement Of Branching Fraction And Direct Cp Asymmetry In Charmless B+ → K+K−Π + Decays At Belle, C.-L. Hsu Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

We report a study of the charmless hadronic decay of the charged B meson to the three-body final state K+K−π+. The results are based on a data sample that contains 772×106  B¯B pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The measured inclusive branching fraction and direct CP asymmetry are (5.38±0.40±0.35)×10−6 and −0.170±0.073±0.017, respectively, where the first uncertainties are statistical and the second are systematic. The K+K− invariant mass distribution of the signal candidates shows an excess in the region below 1.5  GeV/c2, which is consistent with the previous studies from BABAR …


Lepton-Flavor-Dependent Angular Analysis Of B→K^{*}ℓ^{+}ℓ^{-}, S. Wehle Et Al., D. Joffe, Ratnappuli L. Kulasiri Mar 2017

Lepton-Flavor-Dependent Angular Analysis Of B→K^{*}ℓ^{+}ℓ^{-}, S. Wehle Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

We present a measurement of angular observables and a test of lepton flavor universality in the B → K∗ ` +` − decay, where ` is either e or µ. The analysis is performed on a data sample corresponding to an integrated luminosity of 711 fb−1 containing 772 × 106 BB¯ pairs, collected at the Υ(4S) resonance with the Belle detector at the asymmetric-energy e +e − collider KEKB. The result is consistent with Standard Model (SM) expectations, where the largest discrepancy from a SM prediction is observed in the muon modes with a local significance of 2.6σ.


Observation Of D^{0}→Ρ^{0}Γ And Search For Cp Violation In Radiative Charm Decays, T. Nanut Et Al., D. Joffee, Ratnappuli L. Kulasiri Jan 2017

Observation Of D^{0}→Ρ^{0}Γ And Search For Cp Violation In Radiative Charm Decays, T. Nanut Et Al., D. Joffee, Ratnappuli L. Kulasiri

Faculty and Research Publications

We report the first observation of the radiative charm decay D0→ρ0γ and the first search for CP violation in decays D0→ρ0γ, ϕγ, and ¯K*0(892)γ, using a data sample of 943 fb−1 collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. The branching fraction is measured to be B(D0→ρ0γ)=(1.77±0.30±0.07)×10−5, where the first uncertainty is statistical and the second is systematic. The obtained CP asymmetries ACP(D0→ρ0γ)=+0.056±0.152±0.006, ACP(D0→ϕγ)=−0.094±0.066±0.001, and ACP(D0→¯K*0γ)=−0.003±0.020±0.000 are consistent with no CP violation. We also present an improved measurement of the branching fractions B(D0→ϕγ)=(2.76±0.19±0.10)×10−5 and B(D0→¯K*0γ)=(4.66±0.21±0.21)×10−4.


Search For The Rare Decay D^{0}→Γγ At Belle, N. K. Nisar Et Al., D. Joffe Mar 2016

Search For The Rare Decay D^{0}→Γγ At Belle, N. K. Nisar Et Al., D. Joffe

Faculty and Research Publications

We search for the rare radiative decay D 0 → γγ using a data sample with an integrated luminosity of 832 fb−1 recorded by the Belle detector at the KEKB e +e − asymmetric-energy collider. We find no statistically significant signal and set an upper limit on the branching fraction of B(D 0 → γγ) < 8.5 × 10−7 at 90% confidence level. This is the most restrictive limit on the decay channel to date.


First Observation Of The Decay B 0 → Ψ ( 2 S ) Π 0, V. Chobanova Et Al., D. Joffe Feb 2016

First Observation Of The Decay B 0 → Ψ ( 2 S ) Π 0, V. Chobanova Et Al., D. Joffe

Faculty and Research Publications

We report a measurement of the B 0 → ψ(2S)π 0 branching fraction based on the full Υ(4S) data set of 772 × 106 BB¯ pairs collected by the Belle detector at the KEKB asymmetric-energy e +e − collider. We obtain B(B 0 → ψ(2S)π 0 ) = (1.17 ± 0.17(stat) ± 0.08(syst)) × 10−5 . The result has a significance of 7.2 standard deviations and is the first observation of the decay B 0 → ψ(2S)π 0.