Publications (14)0 Total impact
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Article: Search for B -> h(*) nu nubar with the full Belle Y(4S) data sample
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ABSTRACT: We report a search for the rare decays B -> h(*) nu nubar, where h(*) stands for K+, Ks0, K*+, K*0, pi+, pi0, rho+, rho0 and phi. The results are obtained from a 711 fb-1 data sample that contains 772 million BB pairs collected at the Y(4S) resonance with the Belle detector at the KEKB e+e- collider. We search for signal candidates by fully reconstructing a hadronic decay of the accompanying B meson and requiring a single h(*) meson left on the signal side. No significant signal is observed and we set upper limits on the branching fractions at 90% confidence level. The measurements of B+ -> K*+ nu nubar, B+ -> pi+ nu nubar, B0 -> pi0 nu nubar and B0 -> rho^0 nu nubar provide the world's currently most restrictive limits.03/2013; -
Article: Measurement of the CP Violation Parameters in B0 -> pi+ pi- Decays
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ABSTRACT: We present a measurement of the time-dependent CP violation parameters in B0 -> pi+ pi- decays. The results are obtained from the final data sample containing 772 million BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the CP violation parameters Acp = +0.33 +/- 0.06 (stat) +/- 0.03 (syst) and Scp = -0.64 +/- 0.08 (stat) +/- 0.03 (syst), where Acp and Scp represent direct and mixing-induced CP violation, respectively. From an isospin analysis including results from other Belle measurements, we rule out 23.8 < phi2 < 66.8 degrees at the 1 sigma level.02/2013; -
Article: Measurement of the inclusive semileptonic branching fraction Bf(B_s^0 -> X^- l^+ nu) at Belle
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ABSTRACT: We report a measurement of the inclusive semileptonic B_s^0 branching fraction in a 121 fb^{-1} data sample collected near the Upsilon(5S) resonance with the Belle detector at the KEKB asymmetric energy e^+ e^- collider. Events containing B_s^0 pairs are selected by reconstructing a tag side D_s^+ and identifying a signal side lepton l^+ (l = e, mu) that is required to have the same-sign charge to ensure that both originate from different B_s^0 mesons. The B_s^0 -> X^- l^+ nu branching fraction is extracted from the ratio of the measured yields of D_s^+ mesons and D_s^+ l^+ pairs and the known production and branching fractions. The inclusive semileptonic branching fraction is measured to be [10.6 +/- 0.5(stat) +/- 0.7(syst)] %.12/2012; -
Article: Study of B^0 -> rho^0 rho^0 decays, implications for the CKM angle phi_2 and search for other four pion final states
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ABSTRACT: We present a study of the branching fraction of the decay B^0 -> rho^0 rho^0 and the fraction of longitudinally polarized \rho^0 mesons in this decay. The results are obtained from the final data sample containing $772 \times 10^{6}$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We find $166 \pm 59$ B^0 -> rho^0 rho^0 events, corresponding to a branching fraction of ${\cal B}(B^0 -> rho^0 rho^0) = (1.02\pm 0.30 (\rm stat) \pm 0.22 (\rm syst))\times 10^{-6} $ with a longitudinally polarization fraction $f_L = 0.21^{+0.18}_{-0.22} (\rm stat) \pm 0.11 (\rm syst)$. The branching fraction's upper limit is ${\cal B}(B^0 -> rho^0 rho^0) < 1.5 \times 10^{-6}$ at 90% confidence level. We use the longitudinal polarization fraction to determine the Cabibbo-Kobayashi-Maskawa matrix angle $\phi_2 = (91.0 \pm 7.2)^{\circ}$ through an isospin analysis in the $B\to\rho\rho$ system. We furthermore obtain ${\cal B}(B^0 -> rho^0 f_0) \times {\cal B}(f_0 -> \pi^+\pi^-) = (0.86 \pm 0.27 (\rm stat) \pm 0.15 (\rm syst))\times 10^{-6}$, corresponding to $149 \pm 49$ $B^0 -> rho^0 f_0$ events with a significance of 3.0 standard deviations and upper limits at 90% confidence level on the (product) branching fractions for possible decays with the same final state, ${\cal B}(B^0 -> pi^+\pi^-pi^+\pi^-) < 11.7 \times 10^{-6} $, ${\cal B}(B^0 -> rho^0 pi^+\pi^-) < 12.2 \times 10^{-6}$, ${\cal B}(B^0 -> f_0 pi^+\pi^-) \times {\cal B}(f_0->\pi^+\pi^-) < 3.1 \times 10^{-6}$ and ${\cal B}(B^0 -> f_0 f_0) \times {\cal B}(f_0->\pi^+\pi^-)^{2} < 0.2 \times 10^{-6}$.12/2012; -
Article: Study of Three-Body Y(10860) Decays
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ABSTRACT: We report preliminary results on the analysis of the three-body Y(10860)=> B barB pi, Y(10860) => (B barB* + c.c.) pi and Y(10860)=> B* barB* pi decays including an observation of the Y(10860)=> Zb(10610)+- pi-+ => [B barB*+c.c]+- pi-+ and Y(10860)=> Zb(10650)+- pi-+ => [B* barB*]+- pi-+ decays as intermediate channels. We measure branching fractions of the three-body decays to be Br(Y(10860)=> [B barB*+c.c.]+- pi-+)=(28.3+-2.9+-4.6)x10^{-3} and Br(Y(10860)=> [B* barB*]+- pi-+)=(14.1+-1.9+-2.4)x10^{-3} and set 90% C.L. upper limit Br(Y(10860)=> [B barB]+- pi-+)<4.0x10^{-3}. We also report results on the amplitude analysis of the three-body Y(10860)=>Y(nS)pi+pi-, n=1,2,3 decays and the analysis of the internal structure of the three-body Y(10860)=>hb(mP)pi+pi-, m=1,2 decays. The results are based on a 121.4 1/fb data sample collected with the Belle detector at a center-of-mass energy near the Y(10860).09/2012; -
Article: Evidence for B- -> tau- nu_tau-bar with a Hadronic Tagging Method Using the Full Data Sample of Belle
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ABSTRACT: We measure the branching fraction of B- -> tau- nu_tau-bar using the full Upsilon(4S) data sample containing 772*10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events with BBbar pairs are tagged by reconstructing one of the B mesons decaying into hadronic final states, and B- -> tau- nu_tau-bar candidates are detected in the recoil. We find evidence for B- -> tau- nu_tau-bar with a significance of 3.0 standard deviations including systematic errors and measure a branching fraction B(B- -> tau- nu_tau-bar) = [0.72^{+0.27}_{-0.25}(stat) +/- 0.11(syst)] * 10^-4.08/2012; -
Article: First observation of CP violation and improved measurement of the branching fraction and polarization of B0 -> D*+ D*- decays
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ABSTRACT: We report the measurement of the branching fraction, the polarization, and the parameters of the time-dependent CP violation in B0 -> D*+ D*- decays using a data sample of 772 million BB pairs, collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain a branching fraction of B = (7.82 +- 0.38 +- 0.63) x10^{-4}, a CP-odd fraction of R_\perp = 0.138 +- 0.024 +- 0.006 and, additionally, a fraction of the longitudinal component in the transversity base of R_0 = 0.624 +- 0.029 +- 0.011. The measured values of the parameters of the CP violation are S_{D*+ D*-} = -0.79 +- 0.13 +- 0.03 and A_{D*+ D*-} = 0.15 +- 0.08 +- 0.04.07/2012; -
Article: Evidence for a Zb0(10610) in Dalitz analysis of Y(5S) -> Y(nS) pi0 pi0
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ABSTRACT: We report the first observation of Y(5S) -> Y(1,2S) pi0 pi0 decays. Evidence for the Zb0(10610) with 4.9sigma significance is found in a Dalitz plot analysis of Y(5S) -> Y(2S) pi0 pi0 decays. The results are obtained with a 121.4 fb^-1 data sample collected with the Belle detector at the Y(5S) resonance at the KEKB asymmetric-energy e+e- collider.07/2012; -
Article: First measurement of ϕ3 with a model-independent Dalitz plot analysis of B±→DK±, D→KS0π+π- decay
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ABSTRACT: We present the first measurement of the angle ϕ3 of the unitarity triangle using a model-independent Dalitz plot analysis of B±→DK±, D→KS0π+π- decays. The method uses, as input, measurements of the strong phase of the D→KS0π+π- amplitude from the CLEO Collaboration. The result is based on the full data set of 772×106 BB̅ pairs collected by the Belle experiment at the Υ(4S) resonance. We obtain ϕ3=(77.3-14.9+15.1±4.1±4.3)° and the suppressed amplitude ratio rB=0.145±0.030±0.010±0.011. Here the first error is statistical, the second is the experimental systematic uncertainty, and the third is the error due to the precision of the strong-phase parameters obtained by CLEO.Phys. Rev. D. 06/2012; 85(11). -
Article: Measurement of Branching Fraction and First Evidence of CP Violation in B0 --> a1+-(1260) pi-+ Decays
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ABSTRACT: We present a measurement of the branching fraction and time-dependent CP violation parameters in B0 --> a_1^+-(1260) pi^-+ decays. The results are obtained from the final data sample containing 772x10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We also measure an upper limit on the product branching fraction for a possible decay with the same final state B0 --> a_2^+-(1320) pi^-+. In a time-dependent measurement to extract CP asymmetries, we find evidence of mixing-induced CP violation in B0 --> a_1^+-(1260) pi^-+ decays with a 3.1 sigma significance and the rate where the a_1^+-(1260) does not contain the spectator quark is found to dominate the rate where it does at the 4.1 sigma level. However, there is no evidence for either time and flavor integrated direct CP violation or flavor-dependent direct CP violation.05/2012; -
Article: Measurements of branching fractions and time-dependent CP violating asymmetries in B0 → D(*)± D∓ decays
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ABSTRACT: We report measurements of branching fractions and time-dependent CP asymmetries in B{sup 0} {yields} D{sup +}D{sup -} and B{sup 0} {yields} D*{sup {+-}}D{sup {-+}} decays using a data sample that contains (772 {+-} 11) x 10{sup 6} BB{sup -} pairs collected at the {Upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. We determine the branching fractions to be {Beta}(B{sup 0} {yields} D{sup +}D{sup -}) = (2.12 {+-} 0.16 {+-} 0.18) x 10{sup -4} and {Beta}(B{sup 0} {yields} D*{sup {+-}}D{sup {-+}}) = (6.14 {+-} 0.29 {+-} 0.50) x 10{sup -4}. We measure CP asymmetry parameters S{sub D{sup +}D{sup -}} = -1.06{sub -0.14}{sup +0.21} {+-} 0.08 and C{sub D{sup +}D{sup -}} = -0.43 {+-} 0.16 {+-} 0.05 in B{sup 0} {yields} D{sup +}D{sup -} and A{sub D*D} = +0.06 {+-} 0.05 {+-} 0.02, S{sub D*D} = -0.78 {+-} 0.15 {+-} 0.05, C{sub D*D} = -0.01 {+-} 0.11 {+-} 0.04, {Delta}S{sub D*D} = -0.13 {+-} 0.15 {+-} 0.04 and {Delta}C{sub D*D} = +0.12 {+-} 0.11 {+-} 0.03 in B{sup 0} {yields} D*{sup {+-}}D{sup {-+}}, where the first uncertainty is statistical and the second is systematic. We exclude the conservation of CP symmetry in both decays at equal to or greater than 4{sigma} significance.Physical Review. D, Particles, Fields, Gravitation and Cosmology. 05/2012; 85(9). -
Article: First Measurement of phi_3 with a Model-independent Dalitz Plot Analysis of B->DK, D->KsPiPi Decay
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ABSTRACT: We present the first measurement of the angle phi_3 of the Unitarity Triangle using a model-independent Dalitz plot analysis of B->DK, D->KsPiPi decays. The method uses an input measurements of the strong phase of the D->KsPiPi amplitude from the CLEO collaboration. The result is based on the full data set of 772x10^6 BBbar pairs collected by the Belle experiment at the Upsilon(4S) resonance. We obtain phi_3 = (77.3^{+15.1}_{-14.9} +- 4.1 +- 4.3)^{\circ} and the suppressed amplitude ratio r_B = 0.145 +- 0.030 +- 0.010 +- 0.011. Here the first error is statistical, the second is the experimental systematic uncertainty, and the third is the error due to the precision of the strong-phase parameters obtained by CLEO.04/2012; -
Article: Measurements of Branching Fractions and Time-dependent CP Violating Asymmetries in $B^{0} \to D^{(*)\pm}D^{\mp}$ Decays
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ABSTRACT: We report measurements of branching fractions and time-dependent CP asymmetries in $B^{0} \to D^{+}D^{-}$ and $B^{0} \to D^{*\pm}D^{\mp}$ decays using a data sample that contains $(772 \pm 11)\times 10^6 B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We determine the branching fractions to be $\mathcal{B}(B^{0} \to D^{+}D^{-})=(2.12 \pm 0.16 \pm 0.18)\times 10^{-4}$ and $\mathcal{B}(B^{0} \to D^{*\pm}D^{\mp}=(6.14 \pm 0.29 \pm 0.50)\times 10^{-4}$. We measure CP asymmetry parameters $\mathcal{S}_{D^{+}D^{-}} = -1.06_{-0.14}^{+0.21} \pm 0.08$ and $\mathcal{C}_{D^{+}D^{-}} = -0.43 \pm 0.16 \pm 0.05$ in $B^{0} \to D^{+}D^{-}$ and $\mathcal{A}_{D^{*}D} = +0.06 \pm 0.05 \pm 0.02$, $\mathcal{S}_{D^{*}D} = -0.78 \pm 0.15 \pm 0.05$, $\mathcal{C}_{D^{*}D} = -0.01 \pm 0.11 \pm 0.04$, $\Delta\mathcal{S}_{D^{*}D} = -0.13 \pm 0.15 \pm 0.04$ and $\Delta\mathcal{C}_{D^{*}D} = +0.12 \pm 0.11 \pm 0.03$ in $B^{0} \to D^{*\pm}D^{\mp}$, where the first uncertainty is statistical and the second is systematic. We exclude the conservation of CP symmetry in both decays at equal to or greater than $4\sigma$ significance.03/2012; -
Article: Measurements of branching fractions and time-dependent CP violating asymmetries in B0→D(*)±D∓ decays
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ABSTRACT: We report measurements of branching fractions and time-dependent CP asymmetries in B0→D+D- and B0→D*±D∓ decays using a data sample that contains (772±11)×106BB̅ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We determine the branching fractions to be B(B0→D+D-)=(2.12±0.16±0.18)×10-4 and B(B0→D*±D∓)=(6.14±0.29±0.50)×10-4. We measure CP asymmetry parameters SD+D-=-1.06-0.14+0.21±0.08 and CD+D-=-0.43±0.16±0.05 in B0→D+D- and AD*D=+0.06±0.05±0.02, SD*D=-0.78±0.15±0.05, CD*D=-0.01±0.11±0.04, ΔSD*D=-0.13±0.15±0.04 and ΔCD*D=+0.12±0.11±0.03 in B0→D*±D∓, where the first uncertainty is statistical and the second is systematic. We exclude the conservation of CP symmetry in both decays at equal to or greater than 4σ significance.Phys. Rev. D. 85(9).
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Institutions
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2012
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Institut für Technologie und Arbeit
Kaiserslautern, Rhineland-Palatinate, Germany
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