Using kaon secondary interactions in the material of the Belle detector, we search for both inclu... more Using kaon secondary interactions in the material of the Belle detector, we search for both inclusive and exclusive production of the Θ(1540) +. We set an upper limit of 2.5% at the 90% C.L. on the ratio of the Θ(1540) + to Λ(1520) inclusive production cross sections. We also search for the Θ(1540) + as an intermediate resonance in the charge exchange reaction K + n → pK 0 S. An upper limit of Γ Θ + < 0.64 MeV at the 90% C.L. at m Θ + = 1.539 MeV/c 2 is set. These results are obtained from a 397 fb −1 data sample collected with the Belle detector near the Υ(4S) resonance, at the KEKB asymmetric energy e + e − collider.
We report a preliminary measurement of the D0-anti-D0 mixing parameter y_CP and the CP-violating ... more We report a preliminary measurement of the D0-anti-D0 mixing parameter y_CP and the CP-violating parameter A_G using the decay D*+ -> D0 pi+ followed by D0 -> K- pi+ and D0 -> K+ K-. The results are obtained from a 158 fb^-1 data sample collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+ e-
We report preliminary results on the decay $B^{-} \to D^{0}K^{*-}$, $B^{-} \to D_{CP}K^{*-}$ and ... more We report preliminary results on the decay $B^{-} \to D^{0}K^{*-}$, $B^{-} \to D_{CP}K^{*-}$ and its charge c onjugate using a data sample of 95.8 million $B\bar{B}$ pairs recorded at the $\Upsilon(4S)$ resonance with the Belle d etector at the KEKB asymmetric $e^{+}e^{-}$ storage ring. We find the branching fraction for $B^{-} \to D^{0} K^{*-}$ to be ${\cal B} = (5.2
We report measurements and searches for resonant B ± → K ± h → K ± γγ decays where h is a η, η ′ ... more We report measurements and searches for resonant B ± → K ± h → K ± γγ decays where h is a η, η ′ , η c , η c (2S), χ c0 , χ c2 , J/ψ meson or the X(3872) particle. The results are based on a data sample containing 535 million BB pairs collected with the Belle detector at the KEKB e + e − asymmetric-energy collider operating at the Υ(4S) resonance. Signals are observed in the modes with η and η ′ , and we obtain evidence for a signal in the mode with η c. We measure B(B ± → K ± η → K ± γγ) = (0.87 +0.16 −0.15 (stat) +0.10 −0.07 (syst)) × 10 −6 , B(B ± → K ± η ′ → K ± γγ) = (1.40 +0.16 −0.15 (stat) +0.15 −0.12 (syst)) × 10 −6 and B(B ± → K ± η c → K ± γγ) = (0.22 +0.09 −0.07 (stat) +0.04 −0.02 (syst)) × 10 −6. We set upper limits on the branching fractions of the other modes.
We present measurements of the branching fraction, the polarization parameters and CP-violating a... more We present measurements of the branching fraction, the polarization parameters and CP-violating asymmetries in B 0 → D * + D * − decays using a 140 fb −1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB energyasymmetric e + e − collider. We obtain B(B 0 → D * + D * −) = [0.81 ± 0.08(stat) ± 0.11(syst)] × 10 −3 , R ⊥ = 0.19 ± 0.08(stat) ± 0.01(syst), R 0 = 0.57 ± 0.08(stat) ± 0.02(syst), S = −0.75 ± 0.56(stat) ± 0.12(syst) and A = −0.26 ± 0.26(stat) ± 0.06(syst). Consistency with Standard Model expectations is also discussed.
We report a measurement of the branching fraction for τ − → π − π 0 ν τ and the invariant mass sp... more We report a measurement of the branching fraction for τ − → π − π 0 ν τ and the invariant mass spectrum of the resulting π − π 0 system using 72.2 fb −1 of data recorded by the Belle detector at the KEKB e + e − collider. The branching fraction obtained is (25.15 ± 0.04 ± 0.31)%, where the first error is statistical and the second is systematic. The unfolded π − π 0 mass spectrum is used to determine resonance parameters for the ρ(770), ρ ′ (1450), and ρ ′′ (1700) mesons. We also use this spectrum to estimate the hadronic contribution to the anomalous magnetic moment of the muon.
We report a measurement of the exclusive B + meson decay to the D (*)− s K + π + final state usin... more We report a measurement of the exclusive B + meson decay to the D (*)− s K + π + final state using 657 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. We use D * − s
We report a measurement of the branching fraction of the decay B 0 → ρ 0 π 0 , using 386 × 10 6 B... more We report a measurement of the branching fraction of the decay B 0 → ρ 0 π 0 , using 386 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetricenergy e + e − collider. We detect 51 +14 −13 signal events with a significance of 4.2 standard deviations, including systematic uncertainties, and measure the branching fraction to be B B 0 → ρ 0 π 0 = 3.12 +0.88 −0.82 (stat) ± 0.33(syst) +0.50 −0.68 (model) × 10 −6. We also perform the first measurement of direct CP violating asymmetry in this mode.
We report the result of a search for the rare decay B 0 → γγ in 426 fb −1 of data, corresponding ... more We report the result of a search for the rare decay B 0 → γγ in 426 fb −1 of data, corresponding to 226 million B 0 B 0 pairs, collected on the Υ (4S) resonance at the PEP-II asymmetric-energy e + e − collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21 +13 −12 signal events with a statistical signficance of 1.9 σ. This corresponds to a branching fraction B(B 0 → γγ) = (1.7 ± 1.1(stat.) ± 0.2(syst.)) × 10 −7. Based on this result, we set a 90% confidence level upper limit of B(B 0 → γγ) < 3.2 × 10 −7 .
We report the results of a study of two-body B meson decays to the complete set of Kπ, ππ, and KK... more We report the results of a study of two-body B meson decays to the complete set of Kπ, ππ, and KK final states. The study is performed on a data sample of 31.7 ± 0.3 million BB events recorded on the Υ(4S) resonance by the Belle experiment at KEKB. We observe significant signals in all Kπ final states and in the π + π − and π + π 0 final states. We set limits on the π 0 π 0 and KK final states. A search is performed for partial-rate asymmetries between conjugate states for flavor-specific final states.
Evidence for CP-Violating Asymmetries in B 0 → π + π − Decays and Constraints on the CKM Angle φ ... more Evidence for CP-Violating Asymmetries in B 0 → π + π − Decays and Constraints on the CKM Angle φ 2 Typeset by REVT E X
Using kaon secondary interactions in the material of the Belle detector, we search for both inclu... more Using kaon secondary interactions in the material of the Belle detector, we search for both inclusive and exclusive production of the Θ(1540) +. We set an upper limit of 2.5% at the 90% C.L. on the ratio of the Θ(1540) + to Λ(1520) inclusive production cross sections. We also search for the Θ(1540) + as an intermediate resonance in the charge exchange reaction K + n → pK 0 S. An upper limit of Γ Θ + < 0.64 MeV at the 90% C.L. at m Θ + = 1.539 MeV/c 2 is set. These results are obtained from a 397 fb −1 data sample collected with the Belle detector near the Υ(4S) resonance, at the KEKB asymmetric energy e + e − collider.
We report a preliminary measurement of the D0-anti-D0 mixing parameter y_CP and the CP-violating ... more We report a preliminary measurement of the D0-anti-D0 mixing parameter y_CP and the CP-violating parameter A_G using the decay D*+ -> D0 pi+ followed by D0 -> K- pi+ and D0 -> K+ K-. The results are obtained from a 158 fb^-1 data sample collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+ e-
We report preliminary results on the decay $B^{-} \to D^{0}K^{*-}$, $B^{-} \to D_{CP}K^{*-}$ and ... more We report preliminary results on the decay $B^{-} \to D^{0}K^{*-}$, $B^{-} \to D_{CP}K^{*-}$ and its charge c onjugate using a data sample of 95.8 million $B\bar{B}$ pairs recorded at the $\Upsilon(4S)$ resonance with the Belle d etector at the KEKB asymmetric $e^{+}e^{-}$ storage ring. We find the branching fraction for $B^{-} \to D^{0} K^{*-}$ to be ${\cal B} = (5.2
We report measurements and searches for resonant B ± → K ± h → K ± γγ decays where h is a η, η ′ ... more We report measurements and searches for resonant B ± → K ± h → K ± γγ decays where h is a η, η ′ , η c , η c (2S), χ c0 , χ c2 , J/ψ meson or the X(3872) particle. The results are based on a data sample containing 535 million BB pairs collected with the Belle detector at the KEKB e + e − asymmetric-energy collider operating at the Υ(4S) resonance. Signals are observed in the modes with η and η ′ , and we obtain evidence for a signal in the mode with η c. We measure B(B ± → K ± η → K ± γγ) = (0.87 +0.16 −0.15 (stat) +0.10 −0.07 (syst)) × 10 −6 , B(B ± → K ± η ′ → K ± γγ) = (1.40 +0.16 −0.15 (stat) +0.15 −0.12 (syst)) × 10 −6 and B(B ± → K ± η c → K ± γγ) = (0.22 +0.09 −0.07 (stat) +0.04 −0.02 (syst)) × 10 −6. We set upper limits on the branching fractions of the other modes.
We present measurements of the branching fraction, the polarization parameters and CP-violating a... more We present measurements of the branching fraction, the polarization parameters and CP-violating asymmetries in B 0 → D * + D * − decays using a 140 fb −1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB energyasymmetric e + e − collider. We obtain B(B 0 → D * + D * −) = [0.81 ± 0.08(stat) ± 0.11(syst)] × 10 −3 , R ⊥ = 0.19 ± 0.08(stat) ± 0.01(syst), R 0 = 0.57 ± 0.08(stat) ± 0.02(syst), S = −0.75 ± 0.56(stat) ± 0.12(syst) and A = −0.26 ± 0.26(stat) ± 0.06(syst). Consistency with Standard Model expectations is also discussed.
We report a measurement of the branching fraction for τ − → π − π 0 ν τ and the invariant mass sp... more We report a measurement of the branching fraction for τ − → π − π 0 ν τ and the invariant mass spectrum of the resulting π − π 0 system using 72.2 fb −1 of data recorded by the Belle detector at the KEKB e + e − collider. The branching fraction obtained is (25.15 ± 0.04 ± 0.31)%, where the first error is statistical and the second is systematic. The unfolded π − π 0 mass spectrum is used to determine resonance parameters for the ρ(770), ρ ′ (1450), and ρ ′′ (1700) mesons. We also use this spectrum to estimate the hadronic contribution to the anomalous magnetic moment of the muon.
We report a measurement of the exclusive B + meson decay to the D (*)− s K + π + final state usin... more We report a measurement of the exclusive B + meson decay to the D (*)− s K + π + final state using 657 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. We use D * − s
We report a measurement of the branching fraction of the decay B 0 → ρ 0 π 0 , using 386 × 10 6 B... more We report a measurement of the branching fraction of the decay B 0 → ρ 0 π 0 , using 386 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetricenergy e + e − collider. We detect 51 +14 −13 signal events with a significance of 4.2 standard deviations, including systematic uncertainties, and measure the branching fraction to be B B 0 → ρ 0 π 0 = 3.12 +0.88 −0.82 (stat) ± 0.33(syst) +0.50 −0.68 (model) × 10 −6. We also perform the first measurement of direct CP violating asymmetry in this mode.
We report the result of a search for the rare decay B 0 → γγ in 426 fb −1 of data, corresponding ... more We report the result of a search for the rare decay B 0 → γγ in 426 fb −1 of data, corresponding to 226 million B 0 B 0 pairs, collected on the Υ (4S) resonance at the PEP-II asymmetric-energy e + e − collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21 +13 −12 signal events with a statistical signficance of 1.9 σ. This corresponds to a branching fraction B(B 0 → γγ) = (1.7 ± 1.1(stat.) ± 0.2(syst.)) × 10 −7. Based on this result, we set a 90% confidence level upper limit of B(B 0 → γγ) < 3.2 × 10 −7 .
We report the results of a study of two-body B meson decays to the complete set of Kπ, ππ, and KK... more We report the results of a study of two-body B meson decays to the complete set of Kπ, ππ, and KK final states. The study is performed on a data sample of 31.7 ± 0.3 million BB events recorded on the Υ(4S) resonance by the Belle experiment at KEKB. We observe significant signals in all Kπ final states and in the π + π − and π + π 0 final states. We set limits on the π 0 π 0 and KK final states. A search is performed for partial-rate asymmetries between conjugate states for flavor-specific final states.
Evidence for CP-Violating Asymmetries in B 0 → π + π − Decays and Constraints on the CKM Angle φ ... more Evidence for CP-Violating Asymmetries in B 0 → π + π − Decays and Constraints on the CKM Angle φ 2 Typeset by REVT E X
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