Results for " Belle Collaboration"

total 15638took 0.10s
Search for the Electric Dipole Moment of the tau leptonOct 15 2002We have searched for a T/CP violation signature arising from an electric dipole form factor (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an optimal observable method for 29.5 fb^{-1} of data collected with the Belle detector at the ... More
Improved Evidence for Direct CP Violation in B0 --> pi+ pi- Decays and Model-Independent Constraints on phi_2Feb 18 2005May 14 2005We present a new measurement of the time-dependent CP-violating parameters in B0 --> pi+ pi- decays with 275 x 10^6 BB-bar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating at the Upsilon(4S) resonance. We find ... More
Measurement of the e+e- --> D(*)+D(*)- cross-sectionsJul 30 2003Nov 27 2003In this paper we report the first measurement of $e^+e^- \to D^{(*)+}D^{(*)-}$ processes. The cross-sections for $e^+^e- \to D^{*+}D^{*-}$ and $e^+e^- \to D^+D^{*-}$ at $\sqrt{s}=10.58\mathrm{GeV}/c^2$ have been measured to be $0.65 \pm 0.04 \pm 0.07 ... More
Measurement of χ_{c2} Production in Two-Photon CollisionsMay 30 2002The production of the \chi_{c2} charmonium state in two-photon collisions has been measured with the Belle detector at the KEKB e^+e^- collider. A clear signal for \chi_{c2} --> \gamma J/\psi, J/\psi --> l^+l^- is observed in a 32.6fb^{-1} data sample ... More
A High Statistics Study of the Decay tau- -> pi- pi0 nuDec 28 2005We report a measurement of the branching fraction for tau- -> pi- pi0 nu and the invariant mass spectrum of the resulting pi- pi0 system using 72.2 /fb of data recorded by the Belle detector at the KEKB e+e- collider. The branching fraction obtained is ... More
Time-Dependent CP Asymmetries in b --> s qbar q Transitions and sin2phi1 in B0 --> J/psi K0 Decays with 386 Million BBbar PairsJul 08 2005We present measurements of time-dependent CP asymmetries in B0 --> phi(1020) K0, eta' K0, Ks Ks Ks, Ks pi0, f0(980) Ks, omega Ks and K+ K- Ks decays based on a sample of 386 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector ... More
Measurement of Time-Dependent CP-Violating Asymmetries in B0 --> phi Ks0, K+ K- Ks0, and eta' Ks0 DecaysAug 15 2003Nov 12 2003We present an improved measurement of CP-violation parameters in B0 --> phi Ks0, K+ K- Ks0, and eta' Ks0 decays based on a 140 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. ... More
Observation of Large CP Violation in the Neutral B Meson SystemJul 23 2001Aug 01 2001We present a measurement of the Standard Model CP violation parameter sin 2phi_1 based on a 29.1 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. One neutral B meson is fully ... More
Study of charmless B decays to three-kaon final statesAug 19 2002We report on a study of charmless B meson decays to three-kaon final states. The results are obtained with a 78.7 1/fb data sample collected on the Y(4S) resonance by the Belle detector operating at the KEKB asymmetric energy $e^+e^-$ collider. The branching ... More
Charge Asymmetry of Same-Sign Dileptons in $B^0$-$\bar{B}^0$ MixingMay 09 2005We report a measurement of the charge asymmetry for same-sign dileptons in $B^0$-$\bar{B}^0$ mixing, $A_{\rm sl}$. The data were collected with the Belle detector at KEKB. Using a data sample of 78 fb$^{-1}$ recorded at the $\Upsilon(4S)$ resonance and ... More
Measurement of the ratio Br(D0 --> pi+pi-pi0)/Br(D0 --> K-pi+pi0)Oct 20 2006Oct 24 2006We report a high-statistics measurement of the relative branching fraction Br(D0 --> pi+pi-pi0)/Br(D0 --> K-pi+pi0). A 357 inverse fb data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider was used for the analysis. ... More
Measurement of phi1 using B --> D[Ks pi+ pi-] h0Jul 14 2005We present a preliminary measurement of the angle phi1 of the CKM Unitarity Triangle using time-dependent analysis of D -> Ks pi+ pi- decays produced in neutral B meson decay to a neutral D meson and a light meson (B -> D h). The method allows one to ... More
Improved Measurements of Direct CP Violation in B --> K+pi-, K+pi0 and pi+pi0 DecaysJul 11 2005We report an improved measurement of direct CP violation in the decay B0 --> K+pi-, and a search for CP violation in the decays B+ --> K+pi0 and B+ --> pi+pi0. The measured CP violating asymmetries are Acp(K+pi-)=-0.113+-0.022(stat.)+-0.008(syst.), Acp(K+pi0)=0.04+-0.04(stat.)+-0.02(syst.) ... More
Study of B0 -> \bar{D}(*)0 pi+ pi- decaysDec 28 2004We report the results of a study of neutral B decays to the $D^0 \pi^+ \pi^-$ and $D^{*0} \pi^+ \pi^-$ final states using complete $D^{(*)0}$ reconstruction. The contributions from two-body $B\to D^{**} \pi$ with narrow ($j_q=3/2$) $D^{**}$ states and ... More
Study of B+- --> D_CP K+- and D^*_CP K+- decaysJan 18 2006Feb 20 2006We report a study of the modes D_CP K+- and D^*_CP K+- where D^(*) decays to CP eigenstates. The data sample used contains 275 x 10^6 BB events at the Upsilon(4S) resonance collected by the Belle detector at the KEKB energy-asymmetric e^+ e^- collider. ... More
Measurement of Exclusive $B \to X_u \ell ν$ Decays with $D^{(*)} \ell ν$ Decay TaggingAug 08 2005We report a measurement of the charmless semileptonic decays $B^0 \to \pi^- / \rho^- \ell^{+} \nu$ and $B^+ \to \pi^0 / \rho^0 \ell^{+} \nu$, based on 253 fb$^{-1}$ of data collected with the Belle detector at the KEKB $e^+e^-$ asymmetric collider. In ... More
Improved Measurements of B0bar -> DsJ+ K- decaysJul 14 2005We report an improved measurement of the branching fraction for B0bar -> DsJ*(2317)+ K- and present evidence of the B0bar -> DsJ(2460)+ K- decay. These results are obtained from a data sample containing 386 million BBbar pairs that was collected near ... More
Observation of a chi_{c2}' candidate in gamma gamma-->D Dbar production in BelleJul 08 2005We report on a search for the production of new resonance states in the process gamma gamma-->D Dbar. A candidate C-even charmonium state is observed in the vicinity of 3.93 GeV/c^2. The production rate and the angular distribution in the gamma gamma ... More
CP violation in B-$\bar{B}$ mixing with dilepton eventsSep 02 2004We report a measurement of the charge asymmetry for same-sign dileptons in $B^0$-$\bar B^0$ mixing. The data were collected with the Belle detector at KEKB. Using a data sample of 78 fb^{-1} recorded at the $\Upsilon(4S)$ resonance and 9 fb^{-1} recorded ... More
New Measurements of Time-Dependent CP-Violating Asymmetries in B0 -> KsKsKs and Ks pi0 gamma Decays at BelleNov 17 2004Dec 25 2004We present new measurements of CP-violation parameters in B0 -> KsKsKs and Ks pi0 gamma decays based on a sample of 275 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One ... More
Measurement of the Differential $q^2$ Spectrum and Forward-Backward Asymmetry for $B \to K^{(*)} \ell^+ \ell^-$Oct 04 2004Oct 19 2004We report measurements of the differential $q^2$ spectrum and the forward-backward asymmetry for $B \to K^{(*)} \ell^+\ell^-$, where $\ell$ represents an electron or a muon, with a data sample of 253 fb$^{-1}$ accumulated on the $\Upsilon(4S)$ resonance ... More
Moments of the Electron Energy Spectrum in Semileptonic B Decays at BelleSep 03 2004We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a 140 fb^-1 data sample collected near the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric energy e^+ e^- collider. We determine ... More
Search for the b --> d gamma processAug 27 2004We report search results for the flavor-changing neutral current process b --> d gamma with a data sample containing 274 million B meson pairs accumulated at the Upsilon(4S) resonance with the Belle detector at KEKB. We studied the exclusive decays B- ... More
Measurement of Branching Fraction and CP Asymmetry in B-> eta h DecaysAug 25 2004We report measurements of $B$ to pseudoscalar-pseudoscalar decays with at least one eta meson in the final state using 140 fb^{-1} of data collected by the Belle detector at KEKB e^+ e^- collider. We observe the decays of B^+-> eta pi^+ and B^+-> eta ... More
Measurement of the inclusive charmless semileptonic branching fraction of B meson using the full reconstruction tagAug 24 2004We present a preliminary measurement of the inclusive charmless semileptonic branching fraction of the B meson, based on $140 fb^{-1}$ of data collected by the Belle detector at the KEKB $e^+e^-$ asymmetric collider. Events are tagged by fully reconstructing ... More
The anomalous Upsilon(1S)pi+pi- and Upsilon(2S)pi+pi- production near the Upsilon(5S) resonanceJun 18 2008We report the study of e+e- -> Upsilon(1S)pi+pi-, Upsilon(2S)pi+pi-, Upsilon(3S)pi+pi-, and Upsilon(1S)K+K-, near the peak of the Upsilon(5S) resonance. The results are based on a data sample of 21.7 fb^-1 collected with the Belle detector at the KEKB ... More
Time-Dependent CP-Violating Asymmetries in b -> s qbar q TransitionsApr 12 2005Jul 15 2005We present new measurements of CP-violation parameters in B0 -> phiK0, K+K-Ks, f0(980)Ks, eta'Ks, omegaKs and Kspi0 decays based on a sample of 275 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric ... More
Improved Measurements of Partial Rate Asymmetry in B -> h h DecaysJul 14 2004We report improved measurements of the partial rate asymmetry (Acp) in B -> h h decays with 140fb^-1 of data collected with the Belle detector at the KEKB e+e- collider. Here h stands for a charged or neutral pion or kaon and in total five decay modes ... More
Measurement of the branching fractions for $B^0 \to D_s^{*+}π^-$ and $B^0 \to D_s^{*-}K^+$ decaysDec 14 2009Jan 23 2010We present a study of $B^0 \to D_s^{*+}\pi^-$ and $B^0 \to D_s^{*-}K^+$ decays based on a sample of $657 \times 10^6$ $B\bar{B}$ events collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We measure the branching fractions ... More
Measurement of the inclusive $B\to X_{s+d} γ$ branching fraction, photon energy spectrum and HQE parametersAug 08 2016We report a measurement of the inclusive $B\to X_{s+d} \gamma$ and $B\to X_{s} \gamma$ branching fractions using a data set of $(772 \pm 11)\times 10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ... More
Measurement of D0-D0bar mixing and search for CP violation in D0 -> K+K-, pi+pi- decays with the full Belle data setSep 28 2015Dec 21 2015We report an improved measurement of D0-D0bar mixing and a search for CP violation in D0 decays to CP-even final states K+K- and pi+pi-. The measurement is based on the final Belle data sample of 976/fb. The results are y_CP=(1.11 +- 0.22 +- 0.09)% and ... More
First observation of the P-wave spin-singlet bottomonium states h_b(1P) and h_b(2P)Mar 17 2011Aug 23 2011We report the first observation of the spin-singlet bottomonium states h_b(1P) and h_b(2P) produced in the reaction e+e- --> hb(nP)pi+pi- using a 121.4fb-1 data sample collected at energies near the Upsilon(5S) resonance with the Belle detector at the ... More
Study of X(3872) in $B$ meson decaysSep 07 2008We present results on the X(3872), produced in $B^+ \to X(3872) K^+$ and $B^0 \to X(3872) K^0_S$ decays where $X(3872) \to J/\psi \pi^+ \pi^-$. We report the first statistically significant observation of $B^0 \to X(3872) K^0_S$ and measure the ratio ... More
Observation of h_b(1P)->eta_b(1S)gammaOct 18 2011We report the first observation of the radiative transition h_b(1P)->eta_b(1S)gamma, where the h_b(1P) is produced in Upsilon(5S)->h_b(1P)pi+pi- dipion transitions. We measure the eta_b(1S) mass to be (9401.0+-1.9+1.4-2.4)MeV/c^2 with a width of (12.4+5.5-4.6+11.5-3.4)MeV ... More
Measurement of masses of the $Ξ_c(2645)$ and $Ξ_c(2815)$ baryons and observation of $Ξ_c(2980)\toΞ_c(2645)π$ %and observation of the $Ξ_c(2980)$ and observation of $Ξ_c(2980)\to Ξ_c(2645)π$Feb 27 2008We report a precise measurement of the masses of the $\Xi_c(2645)$ and $\Xi_c(2815)$ baryons using a data sample of 414 fb$^{-1}$ collected by the Belle collaboration at the KEKB $e^+ e^-$ collider. The states $\Xi_c(2645)^{0,+}$ are observed in the $\Xi_c^{+,0}\pi^{-,+}$ ... More
Measurement of B(Ds -> munu)Sep 10 2007Feb 21 2008We present a measurement of the branching fraction $B(D_s^+\to\mu^+\nu_\mu)$ using a 548 fb$^{-1}$ data sample collected by the Belle experiment at the KEKB $e^+e^-$ collider. The $D_s$ momentum is determined by reconstruction of the system recoiling ... More
Search for the Electric Dipole Moment of the tau LeptonOct 31 2002Nov 15 2002We have searched for a CP violation signature arising from an electric dipole moment (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an optimal observable method and 29.5 fb^{-1} of data collected with the Belle detector at the KEKB ... More
Measurement of the form factors of the decay B^+\to\bar D^{*0}\ell^+ν_\ell and determination of the CKM matrix element |V_{cb}|Oct 19 2009We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ times the form factor normalization $\mathcal{F}(1)$ using the decay $B^+\to\bar D^{*0}\ell^+\nu_\ell$. This measurement is performed together with a determination of ... More
Study of Michel parameters in leptonic $τ$ decays at BelleSep 17 2014We present a study of Michel parameters in leptonic $\tau$ decays using experimental information collected at the Belle detector. Michel parameters are extracted in the unbinned maximum likelihood fit of the $(\tau^\mp\to\ell^\mp\nu\nu,\tau^\pm\to\pi^\pm\pi^0\nu)$ ... More
Search for double charmonium decays of the P-wave spin-triplet bottomonium statesMar 02 2012Apr 18 2012Using a sample of 158 million $\Upsilon(2S)$ events collected with the Belle detector, we search for the first time for double charmonium decays of the $P$-wave spin-triplet bottomonium states ($\Upsilon(2S) \to \gamma \chi_{bJ}$, $\chi_{bJ} \to \jpsi ... More
Comment on "e+ e- annhilation into J/psi J/psi"Jun 05 2003Using a data sample of 101.8 fb collected by the Belle detector at the KEKB asymmetric energy e+ e- collider, we confirm our published observation of e+ e- -> J/psi eta_c and find no evidence for the process e+ e- -> J/psi J/psi. The latter process was ... More
Precise Measurement of B Meson Lifetimes with Hadronic Decay Final StatesFeb 02 2002Mar 30 2002The lifetimes of the B0bar and B- mesons are extracted from 29.1/fb of data collected with the Belle detector at the KEK B-factory. A fit to the decay length differences of neutral and charged B meson pairs, measured in events where one of the B mesons ... More
Measurement of phi_3 with Dalitz Plot Analysis of B->D(*)K Decay at BelleNov 14 2004Dec 08 2004We present a measurement of the unitarity triangle angle phi_3 using a Dalitz plot analysis of the three-body decay of the neutral D meson from the B->D(*)K process. Using a 253 fb-1 data sample collected by the Belle experiment, we obtain 276 signal ... More
Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decaysNov 09 2001Nov 10 2001We present measurements of the Cabibbo-suppressed decays Lambda_c^+ --> Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+ --> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+ --> p K+ K- and Lambda_c^+ ... More
Measurement of $y_{CP}$ in $D^0$ meson decays to the $K_S^0K^+K^-$ final stateMay 26 2009We present a measurement of the $D^0$-$\overline{D}{}^0$ mixing parameter $y_{CP}$ using a flavor-untagged sample of $D^0\to K_S^0K^+K^-$ decays. The measurement is based on a 673 fb$^{-1}$ data sample recorded with the Belle detector at the KEKB asymmetric-energy ... More
B CP-Violation, Mixing and Lifetime Results from BelleMay 14 2001Recent results on the $B$ CP-violation parameter $\sin2\phi_1$, the $B^0_d$-$\overline{B}^0_d$ mixing parameter $\Delta m_d$ and $B$-meson lifetimes are reported. The results are based on 10.5 $fb^{-1}$ of data collected with the Belle detector at KEKB. ... More
Study of B -> ρπdecays at BelleJul 01 2002This paper describes a study of B meson decays to the pseudoscalar-vector final state \rho\pi using 31.9\times 10^6 B\bar{B} events collected with the Belle detector at KEKB. The branching fractions B(B^+ \to \rho^0\pi^+) = (8.0^{+2.3+0.7}_{-2.0-0.7}) ... More
Observation of the decay $B_s^0\to J/ψη$ and Evidence for $B_s^0\to J/ψη'$Dec 08 2009We report the first observation of $B_s^0\to J/\psi\eta$ and evidence for $B_s^0\to J/\psi\eta'$. These results are obtained from $23.6 \mathrm{fb}^{-1}$ of data collected at the $\Upsilon(5S)$ resonance with the Belle detector at the KEKB $e^+e^-$ collider. ... More
Determination of |V_ub| from Measurements of the Inclusive Charmless Semileptonic Partial Rates of B Mesons using Full Reconstruction TagsMay 27 2005Jan 22 2006We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V_ub|, based on 253 fb^-1 of data collected by the Belle detector at the KEKB e^+e^- asymmetric collider. Events are tagged by fully reconstructing one of the B mesons, produced ... More
High-statistics study of neutral-pion pair production in two-photon collisionsOct 02 2008The differential cross section for the process $\gamma \gamma \to \pi^0 \pi^0$ has been measured in the kinematic range 0.6 GeV $< W < 4.1$ GeV, $|\cos \theta^*|<0.8$ in energy and pion scattering angle, respectively, in the $\gamma\gamma$ center-of-mass ... More
Observation of $ψ(4415)\to D \bar D{}^{*}_2(2460)$ decay using initial-state radiationAug 24 2007Feb 18 2008We report the first observation of the $\psi(4415)$ resonance in the reaction $\e^+e^-\to D^0 D^-\pi^+$ and a measurement of its cross section in the center-of-mass energy range $4.0\mathrm{GeV}$ to $5.0\mathrm{GeV}$ with initial state radiation. From ... More
Search for B0 -> rho0rho0 and Non-Resonant B0 -> 4pi DecaysAug 15 2007We search for the decay B0 -> rho0rho0 and other possible charmless modes with a pi+pi-pi+pi- final state, including B0 -> rho0f0(980), B0 -> f0(980)f0(980), B0 -> f0(980)pipi, B0 -> rho0pipi and non-resonant B0 -> 4pi. These results are obtained from ... More
Improved Measurements of Color-Suppressed Decays B0bar -> D0 pi0, D0 eta and D0 omegaSep 01 2004We present preliminary improved measurements of the branching fractions of the color-suppressed decays B0bar -> D0 h0, where h0 represents the three light neutral mesons pi0, eta and omega. The measurements are based on a data sample of 140fb-1 collected ... More
Evidence for CP-Violating Asymmetries in B0->pi+pi- Decays and Constraints on the CKM Angle phi2Jan 24 2003Apr 03 2003We present an improved measurement of CP-violating asymmetries in B0 -> pi+ pi- decays based on a 78 fb^-1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one neutral B meson ... More
Observation of B->J/psi K1(1270)May 09 2001We report the first observation of the exclusive decay process B->J/psi K1(1270) using a sample of 11.2M BBbar meson pairs collected in the Belle detector at the KEKB asymmetric e+e- collider. We measure branching fractions of Bf(B0 -> J/psi K10(1270) ... More
Measurements of Branching Fractions and Decay Amplitudes in B-> J/ψ K^* decaysMay 10 2002May 15 2002The branching fractions and the decay amplitudes of B -> J/psi K^* decays are measured in a 29.4/fb data sample collected with the Belle detector at the KEKB electron-positron collider. The decay amplitudes of helicity states of the J/psi K^* system are ... More
Measurement of Inclusive Production of Neutral Pions from Upsilon(4S) DecaysMar 26 2001Jun 05 2001Using the Belle detector operating at the KEKB e+e- storage ring, we have measured the mean multiplicity and the momentum spectrum of neutral pions from the decays of the Upsilon(4S) resonance. We measure a mean of 4.70 +/- 0.04 +/- 0.22 neutral pions ... More
Improved measurements of branching fractions and CP partial rate asymmetries for $B\toωK$ and $B\toωπ$Sep 12 2006Dec 22 2006We report improved measurements of $B$ to pseudoscalar-vector decays containing an $\omega$ meson in the final states. Our results are obtained from a data sample that contains $388\times 10^{6}$ $B\bar{B}$ pairs accumulated at the $\Upsilon(4S)$ resonance, ... More
Observation of $B^{\pm} \to ψ(2S) π^{\pm}$ and search for direct CP-violationJul 14 2008Aug 27 2008We report the first observation of $B^{\pm}\to\psi(2S)\pi^{\pm}$, a Cabibbo- and color-suppressed decay. This analysis is based on $657\times10^{6}$ $B\overline B$ events collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric ... More
Search for Lepton-number-violating B+->D-l+l'+ DecaysJul 04 2011We perform the first search for lepton-number-violating B+->D-l+l'+ decays, where l and l' stand for e or mu, using 772 x 10^6 BB-bar pairs accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. No evidence for these ... More
Observation of two charged bottomonium-like resonances in Y(5S) decaysOct 11 2011We report the observation of two narrow structures in the mass spectra of the pi+-Y(nS) (n=1,2,3) and pi+-hb(mP)(m$ (m=1,2) pairs that are produced in association with a single charged pion in Y(5S) decays. The measured masses and widths of the two structures ... More
Observation of B -> D^{(*)} K^- K^{0(*)} decaysJul 17 2002The B -> D^{(*)} K^- K^{(*)0} decays have been observed for the first time. The branching fractions of the B -> D^{(*)} K^- K^{(*)0} decay modes are measured. Significant signals are found for the B -> D^{(*)} K^- K^{*0} and B^- -> D^0 K^- K^0_S decay ... More
Search for new charmonium states in the processes e+ e- --> J/psi D(*) D(*) at sqrt{s} ~ 10.6 GeVAug 28 2007Oct 05 2007We present a study of the X(3940) state in the process e+e- -> J/psi D* Dbar. The X(3940) mass and width are measured to be (3942 +7 -6 +- 6)MeV/c^2 and Gamma=(37 + 26 - 15 +- 8 MeV. In the process e+e- -> J/psi D* D*bar we have observed another charmonium-like ... More
Measurement of Br(Bbar -> D+l-nubar) and Determination of |Vcb|Nov 26 2001Dec 19 2001We present a measurement of the branching fraction for the semileptonic B decay Bbar -> D+l-nubar, where l- can be either an electron or a muon. We find Gamma(Bbar -> D+l-nubar)= (13.79+/-0.76+/-2.51) ns^{-1}, and the resulting branching fraction Br(Bbar ... More
Observation of the decay B^0->D+D*-Jun 06 2002Oct 06 2002We report the first observation of the decay B^0->D+-D*-+ with the Belle detector at the KEKB e^+e^- collider operated at the Upsilon(4S) resonance. The sum of branching fractions B(B^0->D+D*-)+B(B^0->D-D*+) is measured to be (1.17+-0.26+0.22-0.25)x10^-3 ... More
A Measurement of Lifetime Difference in $D^0$ Meson DecaysNov 08 2001Mar 15 2002We report a measurement of the $D^0$-$\bar{D}{}^0$ mixing parameter $y_{CP}$ using 23.4 fb$^{-1}$ of data collected near the $\Upsilon$(4S) resonance with the Belle detector at KEKB. $y_{CP}$ is measured from the lifetime difference of $D^0$ mesons decaying ... More
Measurement of the e+e- --> D0D*-pi+ cross section using initial-state radiationAug 03 2009Nov 19 2009We report measurements of the exclusive cross section for e+e- --> D0D*-pi+ as function of center-of-mass energy from the D0D*-pi+ threshold to 5.2 GeV with initial-state radiation. No evidence is found for Y(4260)-->D0D*-pi+ decays. The analysis is based ... More
Observation of B_s to phi gamma and Search for B_s to gamma gamma Decays at BelleDec 17 2007Feb 26 2008We search for the radiative penguin decays B_s to phi gamma and B_s to gamma gamma in a 23.6 fb-1 data sample collected at the Upsilon(5S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider. We observe for the first time a radiative ... More
Evidence for B to K eta' gamma Decays at BelleOct 05 2008Aug 07 2009We present the results of a search for the radiative decay (B -> K eta' gamma) and find evidence for (B^+ -> K^+ eta' gamma) decays at the 3.3 standard deviation level with a partial branching fraction of (3.6 +/- 1.2 +/- 0.4) x 10e-6, where the first ... More
Search for the dark photon and the dark Higgs boson at BelleJan 31 2015Apr 29 2015The dark photon, $A^\prime$, and the dark Higgs boson, $h^\prime$, are hypothetical constituents featured in a number of recently proposed Dark Sector Models. Assuming prompt decays of both dark particles, we search for their production in the so-called ... More
Measurement Of |V_ub| From Inclusive Charmless Semileptonic B DecaysJul 02 2009Jan 15 2010We present the partial branching fraction for inclusive charmless semileptonic B decays and the corresponding value of the CKM matrix element |Vub|, using a multivariate analysis method to access ~90% of the B -> Xu l nu phase space. This approach dramatically ... More
Improved search for D^0 mixing using semileptonic decays at BelleFeb 20 2008Apr 21 2008A search for mixing in the neutral D meson system has been performed using semileptonic D0 -> K(*)- e+ \nu and D0 -> K(*)- \mu+ \nu decays. Neutral D mesons from D*+ -> D0 \pi_s^+ decays are used and the flavor at production is tagged by the charge of ... More
Observation of two charged bottomonium-like resonancesMay 23 2011Nov 24 2011We report the observation of two narrow structures at 10610MeV/c^2 and 10650MeV/c^2 in the pi^{\pm}Upsilon(nS) (n=1,2,3) and pi^{\pm}h_b(mP) (m=1,2) mass spectra that are produced in association with a single charged pion in Upsilon(5S) decays. The measured ... More
Studies of CP violation in $B^0 \to J/ψK^{*0}$ decaysAug 23 2004Oct 18 2004An angular analysis for B decays into two vector mesons gives parameters sensitive to new physics. They are the decay amplitudes of the three helicity states, the asymmetry in triple product, and the CP violating phase. The measurements of these quantities ... More
Observation of Mixing-induced CP Violation in the Neutral B Meson SystemFeb 13 2002Jul 03 2002This report describes an observation of mixing-induced CP violation and a measurement of the CP violation parameter, sin(2phi_1), with the Belle detector at the KEKB asymmetric e+e- collider. Using a data sample of 29.1 fb-1 recorded on the Upsilon(4S) ... More
Observation of B+ -> chi_c0 K+Nov 22 2001Nov 23 2001Using a sample of $31.3 x 10^6 $B\bar{B}$ pairs collected with the Belle detector at the Y(4S) resonance, we make the first observation of the charged B meson decay to chi_c0 and a charged kaon. The measured branching fraction is Br(B+ -> chi_c0 K+)=(6.0^{+2.1}_{-1.8}\pm1.1)x10^{-4}, ... More
Determination of |Vcb| using the semileptonic decay \bar{B}^0 --> D^{*+}e^-\barνNov 19 2001Dec 19 2001We present a measurement of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |Vcb| using a 10.2 fb^{-1} data sample recorded at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring. By extrapolating the differential ... More
Measurement of Time-Dependent CP-Violating Asymmetries in B0 -> KsKsKs Decay Measurement of Time-Dependent CP-Violating Asymmetries in B0 -> KsKsKs DecayMar 13 2005Sep 06 2005We present a measurement of CP-violation parameters in the B0 -> KsKsKs decay based on a sample of 275 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is ... More
Study of intermediate two-body decays in $\bar{B}^0\to Σ_c(2455)^{0}\bar{p}π^{+}$Aug 27 2008We present results of a detailed study of the three-body $\bar{B}^0\to\Sigma_c(2455)^{0}\bar{p}\pi^{+}$ decay. A significant enhancement of signal events is observed in the $\bar{p}\pi^+$ mass system near $1.5 {\rm GeV}/c^2$ that is consistent with the ... More
Measurement of B- -> tau- nu_tau-bar Decay With a Semileptonic Tagging MethodSep 23 2008We present a new measurement of the decay B- -> tau- nu_tau-bar with a semileptonic B tagging method, using a data sample containing 657*10^6 BB-bar pairs collected at the (4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider. A ... More
Study of $\bar{B^0}\to {D}^0 π^+ π^-$ decaysNov 29 2006We report the results of a study of neutral B meson decays to the D^0 pi+ pi- final state, where the D^0 is fully reconstructed. The results are obtained from an event sample containing 388 million BB-bar -meson pairs collected in the Belle experiment ... More
Measurement of neutral pion pair production in two-photon collisionsNov 13 2007The differential cross section of the process gamma gamma -> pi^0 pi^0 has been measured in the kinematical range 0.6 GeV < W < 4.0 GeV and |cos theta*|<0.8 in energy and pion scattering angle, respectively, in the gamma gamma center-of-mass system. We ... More
Search for lepton flavor violating $τ\to \ell V^0$ decays at BelleAug 24 2007We have searched for neutrinoless $\tau$ lepton decays into $\ell$ and $V^0$, where $\ell$ stands for an electron or muon, and $V^0$ for a vector meson ($\phi$, $\omega$, $K^{*0}$ or $\bar{K}^{*0}$), using 543 fb$^{-1}$ of data collected with the Belle ... More
Observation of a new DsJ meson in B+ -> D0-bar D0 K+ decaysAug 10 2006We report the observation of a new DsJ meson produced in B+ -> D0-bar DsJ -> D0-bar D0 K+. This state has a mass of M = 2715 +-11(stat) +11-14(syst) MeV/c^2, a width Gamma = 115 +-20(stat) +36-32(syst) MeV/c^2 and a spin-parity 1-. The results are based ... More
Study of three-body charmless B decays at BelleJul 20 2001Using a data sample of 21.3 fb$^{-1}$ collected by the Belle detector, three body charmless decays $B^+\to K^+ h^+ h^-$ have been studied. With no assumptions on the intermediate mechanisms, the following branching fractions have been measured for the ... More
Measurement of B -> D*- tau+ nu and B -> h(*) nu nubar Decays at BelleAug 30 2007Aug 31 2007We report an observation of the decay B0 -> D*- tau+ nu and a search for the rare decays B -> h(*) nu nubar\ove, where h(*) stands for a light meson. A data sample of 535 million BBbar pairs collected with the Belle detector at the KEKB e+e- collider ... More
Study of charmonia in four-meson final states produced in two-photon collisionsJun 27 2007Dec 10 2007We report measurements of charmonia produced in two-photon collisions and decaying to four-meson final states, where the meson is either a charged pion or a charged kaon. The analysis is based on a 395fb^{-1} data sample accumulated with the Belle detector ... More
Observation of a charmonium-like enhancement in the gamma gamma --> omega J/psi processDec 22 2009Mar 10 2010We report the results of a search for a charmonium-like state produced in the process gamma gamma --> omega J/psi in the 3.9-4.2 GeV/c^2 mass region. We observe a significant enhancement, which is well-described by a resonant shape with mass M = (3915 ... More
Measurement of the form factors of the decay B^0 -> D^{*-} l^+ nu_l and determination of the CKM matrix element |V_{cb}|Oct 09 2008This paper describes a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ using the decay $B^0\to D^{*-}\ell^+\nu_\ell$. We perform a combined measurement of this quantity and of the form factors $\rho^2$, $R_1(1)$, and $R_2(1)$ ... More
Measurement of the Differential Branching Fraction and Forward-Backward Asymmetry for B->K(*)l+l-Oct 02 2008We study B->K(*)l+l- decays based on a large data sample of 657 million BB pairs collected with the Belle detector at the KEKB e+e- collider. The differential branching fraction, the isospin asymmetry, the K* polarization, and the forward-backward asymmetry ... More
Measurements of Branching Fractions for B0 --> Ds+pi- and B0-bar --> Ds+K-Jul 27 2010Oct 01 2010We present improved measurements of the branching fractions for the decays B0 --> Ds+pi- and B0-bar --> Ds+K- using a data sample of 657x10^6 BB-bar events collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. ... More
Search for \bar{B}^0\toΛ_c^+\barΛ_c^- decay at BelleAug 08 2007Oct 06 2007We search for the doubly charmed baryonic decay $\bar{B}^0\to\Lambda_c^+\bar{\Lambda}_c^-$, in a data sample of $520\times10^6$ $B{\bar B}$ events accumulated at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric e^+e^- collider. ... More
Search for Lepton Flavor Violating tau^- Decays into l^-eta, l^-eta' and l^-pi^0Sep 08 2006Oct 17 2006We have searched for lepton flavor violating $\tau$ decays with a pseudoscalar meson ($\eta$, $\eta'$ and $\pi^0$) using a data sample of 401 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No evidence for ... More
Study of $B^0 \to ηK^+ π^-$ and $ηπ^+ π^-$Sep 02 2005We report results of studies of inclusive $B \to \eta K^+ \pi^-$ and $B \to \eta \pi^+ \pi^-$ decays. Charged conjugates are implied throughout this paper. These are obtained from a data sample containing 386 million $B\bar{B}$ pairs, collected at the ... More
Improved Measurements of Branching Fractions and CP Asymmetries in B-> eta h DecaysAug 12 2005We report improved measurements of B decays with an eta meson in the final state using 357 fb^-1 of data collected by the Belle detector at the KEKB e^+ e^- collider. We observe the decays B^+- ->eta pi^+- and B^+- -> eta K^+-; the measured branching ... More
Observation of a new charmonium state in double charmonium production in e+ e- annihilation at \sqrt{s} ~ 10.6 GeVJul 04 2005Nov 08 2005We report the first observation of a new charmonium state at a mass of $(3.943 \pm 0.006 \pm 0.006) {GeV}/c^2$. This state, called X(3940), is observed in the process $e^+ e^- \to J/\psi X(3940)$ in the spectrum of masses recoiling against a reconstructed ... More
High statistics study of f_0(980) resonance in gamma gamma --> pi^+ pi^- productionOct 13 2006Jan 05 2007We report on a high statistics measurement of the cross section of the process gamma gamma to pi^+ pi^- in the center-of-mass energy range 0.8 GeV/c^2 < W < 1.5 GeV/c^2 with 85.9 fb^-1 of data collected at sqrt(s)=10.58 GeV and 10.52 GeV with the Belle ... More
Measurement of masses of $Ξ_c(2645)$ and $Ξ_c(2815)$ baryonsAug 04 2006We report a precise measurement of masses of the $\Xi_c(2645)$ and $\Xi_c(2815)$ baryons using data collected by the Belle experiment at the KEKB $e^+ e^-$ collider. The states $\Xi_c(2645)^{0,+}$ are observed in the $\Xi_c^{+,0}\pi^{-,+}$ decay modes, ... More
Measurement of K^+K^- production in two-photon collisions in the resonant-mass regionSep 29 2003Nov 18 2003K^+K^- production in two-photon collisions has been studied using a large data sample of 67 fb^{-1} accumulated with the Belle detector at the KEKB asymmetric e^+e^- collider. We have measured the cross section for the process gamma gamma -> K^+ K^- for ... More
Observation of Double cc bar Production in e+ e- Annihilation at sqrt{s} ~ 10.6 GeVMay 31 2002We report the observation of prompt J/psi via double ccbar production from the e+e- continuum. In this process one ccbar pair fragments into a J/psi meson while the remaining pair either produces a bound charmonium state or fragments into open charm. ... More