Results for " Belle Collaboration"

total 13572took 0.24s
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
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
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
Search for $B$ decays to final states with the $η_c$ mesonSep 09 2015We report a search for $B$ decays to selected final states with the $\eta_c$ meson: $B^{\pm}\to K^{\pm}\eta_c\pi^+\pi^-$, $B^{\pm}\to K^{\pm}\eta_c\omega$, $B^{\pm}\to K^{\pm}\eta_c\eta$ and $B^{\pm}\to K^{\pm}\eta_c\pi^0$. The analysis is based on $772\times ... More
Search for charmonium and charmonium-like states in $Υ(1S)$ and $Υ(2S)$ radiative decaysAug 04 2012Using samples of 102 million $\Upsilon(1S)$ and 158 million $\Upsilon(2S)$ event samples collected with the Belle detector, we report on the first search for charge-parity-even charmonium and charmonium-like states in $\Upsilon(1S)$ and $\Upsilon(2S)$ ... More
Measurement of the branching fractions for B- --> D(*)+ pi- l- nu-bar and B0bar --> D(*)0 pi+ l- nu-barJul 13 2005Aug 17 2005We report on a measurement of the branching fractions for B- --> D(*)+ pi- l- nu-bar and B0bar --> D(*)0 pi+ l- nu-bar with 275 million BBbar events collected at the Upsilon(4S) resonance with the Belle detector at KEKB. Events are tagged by fully reconstructing ... More
Observation of candidate exotic mesons containing heavy quarks with BelleOct 20 2008We report the observation of two resonance-like structures in the $\pi^+ \chi_{c1}$ invariant mass distribution near 4.1 GeV in exclusive $B\to K\pi^+\chi_{c1}$ decays. A detailed Dalitz-plot analysis demonstrates that these structures cannot be produced ... 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
Open Charm decays and spectroscopy at BelleNov 14 2016In this review we report the recent results of open charm decays and spectroscopy using the data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider.
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
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 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
Observation of a near-threshold omega-J/psi mass enhancement in exclusive B-->K omega J/psi decaysAug 25 2004Dec 23 2004We report the observation of a near-threshold enhancement in the omega-J/psi invariant mass distribution for exclusive B-->K omega J/psi decays. The results are obtained from a 253 fb-1 data sample that contains 275 million BB-bar meson pairs that were ... 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
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
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
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
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
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 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
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
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
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
Study of B-> phi phi K DecaysFeb 11 2008We report an observation of the decay B^\pm -> \phi \phi K^\pm and evidence for B^0 -> \phi \phi K^0. These results are based on a 414 fb^{-1} data sample collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider operating at the ... 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
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
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
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
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 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
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 $0.65 \pm 0.04 \pm 0.07 ... More
Measurement of χ_{c2} Production in Two-Photon CollisionsMay 30 2002The production of the \chi_{c2} charmonium state in two-photon collisions has been measured with the Belle detector at the KEKB e^+e^- collider. A clear signal for \chi_{c2} --> \gamma J/\psi, J/\psi --> l^+l^- is observed in a 32.6fb^{-1} data sample ... More
Observation of two charged bottomonium-like resonances in Y(5S) decaysOct 11 2011We report the observation of two narrow structures in the mass spectra of the pi+-Y(nS) (n=1,2,3) and pi+-hb(mP)(m$ (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
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
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
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
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
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
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
Observation of $B^{\pm}\to p \bar{p} K^{\pm}$Feb 07 2002We report the observation of the decay mode $B^{\pm}\to p \bar{p} K^{\pm}$ based on an analysis of 29.4 fb$^{-1}$ of data collected by the Belle detector at KEKB. This is the first example of a $b\to s$ transition with baryons in the final state. The ... 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
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
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
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
Improved Measurement of the Electroweak Penguin Process B->XsllMar 24 2005We present an improved measurement of the branching fraction for the electroweak penguin process B->Xsll, where l is an electron or a muon and Xs is a hadronic system containing an s-quark. The measurement is based on a sample of 152*10^6 Upsilon(4S) ... More
Measurement of Azimuthal Asymmetries in Inclusive Production of Hadron Pairs in e+e- Annihilation at BelleJul 14 2005Jul 11 2006The Collins effect connects transverse quark spin with a measurable azimuthal dependence in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods we observe statistically significant azimuthal asymmetries ... More
Measurement of Branching Fractions for $B\to χ_{c1(2)} K (K^*)$ at BelleAug 14 2005Dec 24 2005We have measured the branching fractions for the exclusive decay modes $B\to {\chi}_{c1(2)} K(K^*)$ using a $140~{\rm fb}^{-1}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The measured branching fractions ... More
Measurement of B -> D_s K pi branching ratiosAug 21 2007We report a measurement of the exclusive $B^+$ meson decay to the final state $D_s^- K^+\pi^+$ using $520 \times 10^{6} B\bar{B}$ pairs collected near the $\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. ... More
Search for B0 -> K*0 nu nubar Using One Fully Reconstructed B MesonAug 17 2006We present a search for the rare decay B0 -> K*0 nu nubar, using a data sample of 492 fb^-1 collected with the Belle detector at the KEKB e+e- collider. Signal candidates are required to have an accompanying B meson fully reconstructed in one of the hadronic ... More
Study of time-dependent CP-violation in $B^0 \to J/ψ~π^0$ decayAug 21 2003We report a measurement of CP asymmetry parameters in the $b \to c\bar{c}d$-transition-induced decays $B^0(\bar{B^0}) \to J/\psi pi^0$. The analysis is based on a 140 fb$^{-1}$ data sample accumulated at the $\Upsilon(4S)$ resonance by the Belle detector ... More
Measurement of CP-Violation Parameter sin(2phi1) with 152 Million BB-bar PairsAug 15 2003We present a precise measurement of the standard model CP-violation parameter sin(2phi1) based on a sample of 152 x 10^6 BB-bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. One neutral ... More
Search for Charmless Two-body Baryonic Decays of B MesonsMar 19 2002We report the results of a search for the rare baryonic decays $B^0 \to p\bar{p}$, $\Lambda\bar{\Lambda}$, and $B^+ \to p\bar{\Lambda}$. The analysis is based on a data set of $31.7\times 10^6 B\bar{B}$ events collected by the Belle detector at the KEKB ... More
Observation of $B^+ \to χ_{c0} K^+ $Jul 20 2001We report the first observation of the decay $B^+ \to \chi_{c0} K^+$ using 21.3 fb$^{-1}$ of data collected by the Belle detector at the $\Upsilon$(4S) resonance. The preliminary result for the branching fraction is ${\cal{B}}(B^+\to \chi_{c0}K^+)=(8.0^{+2.7}_{-2.4}\pm ... More
Search for Lepton Flavor Violating tau Decays into Three LeptonsAug 24 2007We search for lepton-flavor-violating tau decays into three leptons (electron or muon) using 535 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. No evidence for these decays is observed and we set 90% confidence ... More
Precise measurement of hadronic $τ$-decays in modes with $η$ mesonsAug 06 2007We have measured branching fractions of hadronic $\tau$ decays involving an $\eta$ meson using 485 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We obtain the following branching fractions: ${\cal B}(\tau^-\to ... More
Search for Direct CP Violation in Three-Body Charmless B+- => K+-pi+-pi-+ DecayAug 31 2005We report results on studies of CP violation in the three-body charmless decay B+- => K+-pi+-pi-+. Evidence at the 3.9sigma level for large direct CP violation in B+- => rho(770)0K+-$ is found. This is the first evidence for CP violation in a charged ... More
Improved Measurement of CP-Violation Parameters sin(2phi1) and |lambda|, B Meson Lifetimes, and B0-B0bar Mixing Parameter Delta m_dAug 23 2004Apr 12 2005We present a precise measurement of the standard model CP-violation parameter sin(2phi1), the direct CP violation parameter |lambda|, the lifetimes of charged and neutral B mesons and their ratio, and the B0-B0bar mixing parameter Delta m_d based on a ... More
Improved Measurement of Mixing-induced CP Violation in the Neutral B Meson SystemAug 16 2002Oct 28 2002We present an improved measurement of the standard model CP violation parameter sin2phi_1 (also known as sin2beta) based on a sample of 85 times 10^6 B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy ... More
Belle B Physics ResultsNov 10 2001B physics results from the Belle experiment are reviewed. Precise measurements of Cabbibo-Kobayashi-Maskawa matrix elements are made. Several decay modes are observed which will enable us to measure the CP angles, phi_i in channels other than B0->psi ... More
Observation of e+e- to K+K-J/psi via Initial State Radiation at BelleSep 17 2007Dec 05 2007The process e+e- to K+K-J/psi is observed for the first time via initial state radiation. The cross section of e+e- to K+K-J/psi for center-of-mass energies between threshold and 6.0 GeV is measured using 673 fb^{-1} of data collected with the Belle detector ... More
Measurement of exclusive B to Xu l nu decays using full-reconstruction tagging at BelleDec 08 2008We report on a study of the branching fractions for the exclusive charmless semileptonic B decay modes B to pi+ l nu, B to pi0 l nu, B to rho+ l nu, B to rho0 l nu and B to omega l nu, using events tagged by fully reconstructing one of the B mesons in ... More
Measurement of $y_{CP}$ in $D$ meson decays to CP eigenstatesAug 01 2008We 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 by the Belle detector at the KEKB asymmetric-energy ... More