We present improved measurements of the branching fractions of the color-suppressed decays B¯0--&... more We present improved measurements of the branching fractions of the color-suppressed decays B¯0-->D(*)0h0, where h0 represents a light neutral meson pi0, eta or omega. The measurements are based on a data sample of 140fb-1 collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider, corresponding to 7 times the luminosity of the previous Belle measurements.
Using the inclusive photon spectrum based on a data sample collected at the $J/\psi$ peak with th... more Using the inclusive photon spectrum based on a data sample collected at the $J/\psi$ peak with the KEDR detector at the VEPP-4M $e^+e^-$ collider, we measured the rate of the radiative decay $J/\psi\to\gamma\eta_{\rm c}$ as well as $\eta_{\rm c}$ mass and width. Taking into account an asymmetric photon lineshape we obtained: $\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33}$ keV, $M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6}$ MeV/$c^2$, $\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6}$ MeV.
We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the... more We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e+e− collider. We measure the branching fraction of radiative decay J/ψ → ηcγ, ηc width and mass. Our preliminary results are: M(ηc) = 2979.4±1.5±1.9 MeV/c2, Γ(ηc) = 27.8±5.1±3.3 MeV, Γ(J/ψ→ ηcγ) = (2.34±0.15±0.40)%.
ABSTRACT A project of a Super Charm-Tau factory is being developed at the Budker Institute of Nuc... more ABSTRACT A project of a Super Charm-Tau factory is being developed at the Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) in Novosibirsk. The electron–positron collider to be employed will operate at c.m. energies in the range between 2 and 5 GeV at an unprecedentedly high luminosity of 1035 cm−2 s−1 with a longitudinal electron polarization at the beam-interaction point. The main objective of experiments at the Super Charm-Tau factory is to study processes involving the production and properties of charmed quarks and tau leptons. A high luminosity of this setup will make it possible to obtain a statistical data sample that will be three to four orders of magnitude vaster than that from any other experiment performed thus far. Experiments at this setup are assumed to be sensitive to effects of new physics beyond the Standard Model. Investigations to be carried out at the Super-Charm- Tau factory will supplement future experiments at Super-B factories under construction in Italy and in Japan.
We present a measurement of the branching fraction for the semileptonic /B decay B¯0--&am... more We present a measurement of the branching fraction for the semileptonic /B decay B¯0-->D+l-nu¯, where l- can be either an electron or a muon. We find Gamma(B¯0-->D+l- nu¯)=(13.79+/-0.76+/-2.51) ns-1, and the resulting branching fraction B(B¯0-->D+l-nu¯)=(2.13+/- 0.12+/-0.39)%, where the first error is statistical and the second systematic. We also investigate the B¯0-->D+l-nu¯ form factor and the implications of the result for
We report the observation of B0 decays to the K+pi-pi0 final state using a data sample of 78 fb-1... more We report the observation of B0 decays to the K+pi-pi0 final state using a data sample of 78 fb-1 collected by the Belle detector at the KEKB e+e- collider. With no assumptions about intermediate states in the decay, the branching fraction is measured to be (36.6-4.3+4.2±3.0)×10-6. We also search for B decays to intermediate two-body states with the same K+pi-pi0
The masses of the neutral and charged D mesons have been measured with the KEDR detector at the V... more The masses of the neutral and charged D mesons have been measured with the KEDR detector at the VEPP-4M electron-positron collider: M D 0 = 1865.30 ± 0.33 ± 0.23 MeV, M D + = 1869.53 ± 0.49 ± 0.20 MeV. address: [email protected] (A.O. Poluektov). according to some models, is a bound state of D 0 and D * 0 mesons [5] and has a mass very close to the sum of the D 0 and D * 0 meson masses. Presently, the world-average D 0 mass value [6] (M D 0 = 1864.84 ± 0.17 MeV) is dominated by the CLEO measurement M D 0 = 1864.847 ± 0.150(stat) ± 0.095(syst) MeV [7]
We have searched for neutrinoless τ lepton decays into three charged leptons using an 87.1 fb −1 ... more We have searched for neutrinoless τ lepton decays into three charged leptons using an 87.1 fb −1 data sample collected with the Belle detector at the KEKB e + e − collider. Since the number of signal candidate events is compatible with that expected from the background, we set 90% confidence level upper limits on the branching fractions in the range (1.9-3.5) × 10 −7 for various decay modes τ − → − + − where represents e or µ. 2004 Published by Elsevier B.V.
We report the first observation of e;{+}e;{-}-->Upsilon(1S... more We report the first observation of e;{+}e;{-}-->Upsilon(1S)pi;{+}pi;{-}, Upsilon(2S)pi;{+}pi;{-}, and first evidence for e;{+}e;{-}-->Upsilon(3S)pi;{+}pi;{-}, Upsilon(1S)K+K-, near the peak of the Upsilon(5S) resonance at sqrt[s] approximately 10.87 GeV. The results are based on a data sample of 21.7 fb;{-1} collected with the Belle detector at the KEKB e;{+}e;{-} collider. Attributing the signals to the Upsilon(5S) resonance, the partial widths Gamma(Upsilon(5S)-->Upsilon(1S)pi;{+}pi;{-})=0.59+/-0.04(stat)+/-0.09(syst) MeV and Gamma(Upsilon(5S)-->Upsilon(2S)pi;{+}pi;{-})=0.85+/-0.07(stat)+/-0.16(syst) MeV are obtained from the observed cross sections. These values exceed by more than 2 orders of magnitude the previously measured partial widths for dipion transitions between lower Upsilon resonances.
The B meson decay modes B--&a... more The B meson decay modes B-->Dpp; and B-->D(*)pp; have been studied using 29.4 fb(-1) of data collected with the Belle detector at KEKB. The B;(0)-->D(0)pp; and B;(0)-->D(*0)pp; decays have been observed for the first time with branching fractions B(B;(0)-->D(0)pp;)=(1.18+/-0.15+/-0.16)x10(-4) and B(B;(0)-->D(*0)pp;)=(1.20(+0.33)(-0.29)+/-0.21)x10(-4). No signal has been found for the B+-->D(+)pp; and B+-->D(*+)pp; decay modes, and the corresponding upper limits at 90% C.L. are presented.
We report evidence for B(0) --> D(0)D(-) and the first observation... more We report evidence for B(0) --> D(0)D(-) and the first observation of the decay modes B(-) --> D(0)D(-) and B(-) --> D(0)D(*-) based on a sample of 152 x 10(6) BB events collected by the Belle detector at KEKB. The branching fractions for B(0) --> D(+) D(-), B--->D(0)D(-), and B--> D(0)D(*-) are found to be (1.91 +/- 0.51 +/- 0.30) x10(-4), (4.83 +/- 0.78 +/- 0.58) x 10(-4), and (4.57 +/- 0.71 +/- 0.56) x 10(-4), respectively. Charge asymmetries in the B---> D(0)D(-) and B(-) --> D(0)D(*-) channels are consistent with zero.
We present a search for the rare decays B --> h(*)nunu[over ], whe... more We present a search for the rare decays B --> h(*)nunu[over ], where h(*) stands for a light meson. A data sample of 535 x 10{6} BB[over ] pairs collected with the Belle detector at the KEKB e{+}e{-} collider is used. Signal candidates are required to have an accompanying B meson fully reconstructed in a hadronic mode and signal side particles consistent with a single h(*) meson. No significant signal is observed and we set upper limits on the branching fractions at 90% confidence level. The limits on B{0} --> K{*0}nunu[over ] and B{+} --> K{+}nunu[over ] decays are more stringent than the previous constraints, while the first searches for B{0} --> K{0}nunu[over ], pi{0}nunu[over ], rho{0}nunu[over ], varphinunu[over ] and B{+} --> K{*+}nunu[over ], rho{+}nunu[over ] are reported.
We report the first observation of a B meson decay that is not accessible by a direct spectator p... more We report the first observation of a B meson decay that is not accessible by a direct spectator process. The channel B(0)-->D(+)(s)K- is found in a sample of 85 x 10(6) BB; events, collected with the Belle detector at KEKB, with a branching fraction B(B(0)-->D(+)(s)K-)=(4.6(+1.2)(-1.1)+/-1.3) x 10(-5). We also obtain evidence for the B0-->D(+)(s)pi(-) decay with branching fraction B(B0-->D(+)(s)pi(-))=(2.4(+1.0)(-0.8)+/-0.7) x 10(-5). This value may be used to extract a model-dependent value of |V(ub)|.
We report the observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370), which are CP ei... more We report the observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370), which are CP eigenstate decay modes. These results are obtained from 121.4 fb⁻¹ of data collected at the Υ(5S) resonance with the Belle detector at the KEKB e(+)e⁻ collider. We measure the branching fractions B(B(s)⁰→J/ψf₀(980); f₀(980)→π(+)π⁻)=(1.16(-0.19)(+0.31)(stat)(-0.17)(+0.15)(syst)(-0.18)(+0.26)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 8.4σ, and B(B(s)⁰→J/ψf₀(1370); f₀(1370)→π(+)π⁻)=(0.34(-0.14)(+0.11)(stat)(-0.02)(+0.03)(syst)(-0.05)(+0.08)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 4.2σ. The last error listed is due to uncertainty in the number of produced B(s)((*))B(s)((*)) pairs.
We present improved measurements of the branching fractions of the color-suppressed decays B¯0--&... more We present improved measurements of the branching fractions of the color-suppressed decays B¯0-->D(*)0h0, where h0 represents a light neutral meson pi0, eta or omega. The measurements are based on a data sample of 140fb-1 collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider, corresponding to 7 times the luminosity of the previous Belle measurements.
Using the inclusive photon spectrum based on a data sample collected at the $J/\psi$ peak with th... more Using the inclusive photon spectrum based on a data sample collected at the $J/\psi$ peak with the KEDR detector at the VEPP-4M $e^+e^-$ collider, we measured the rate of the radiative decay $J/\psi\to\gamma\eta_{\rm c}$ as well as $\eta_{\rm c}$ mass and width. Taking into account an asymmetric photon lineshape we obtained: $\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33}$ keV, $M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6}$ MeV/$c^2$, $\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6}$ MeV.
We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the... more We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e+e− collider. We measure the branching fraction of radiative decay J/ψ → ηcγ, ηc width and mass. Our preliminary results are: M(ηc) = 2979.4±1.5±1.9 MeV/c2, Γ(ηc) = 27.8±5.1±3.3 MeV, Γ(J/ψ→ ηcγ) = (2.34±0.15±0.40)%.
ABSTRACT A project of a Super Charm-Tau factory is being developed at the Budker Institute of Nuc... more ABSTRACT A project of a Super Charm-Tau factory is being developed at the Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) in Novosibirsk. The electron–positron collider to be employed will operate at c.m. energies in the range between 2 and 5 GeV at an unprecedentedly high luminosity of 1035 cm−2 s−1 with a longitudinal electron polarization at the beam-interaction point. The main objective of experiments at the Super Charm-Tau factory is to study processes involving the production and properties of charmed quarks and tau leptons. A high luminosity of this setup will make it possible to obtain a statistical data sample that will be three to four orders of magnitude vaster than that from any other experiment performed thus far. Experiments at this setup are assumed to be sensitive to effects of new physics beyond the Standard Model. Investigations to be carried out at the Super-Charm- Tau factory will supplement future experiments at Super-B factories under construction in Italy and in Japan.
We present a measurement of the branching fraction for the semileptonic /B decay B¯0--&am... more We present a measurement of the branching fraction for the semileptonic /B decay B¯0-->D+l-nu¯, where l- can be either an electron or a muon. We find Gamma(B¯0-->D+l- nu¯)=(13.79+/-0.76+/-2.51) ns-1, and the resulting branching fraction B(B¯0-->D+l-nu¯)=(2.13+/- 0.12+/-0.39)%, where the first error is statistical and the second systematic. We also investigate the B¯0-->D+l-nu¯ form factor and the implications of the result for
We report the observation of B0 decays to the K+pi-pi0 final state using a data sample of 78 fb-1... more We report the observation of B0 decays to the K+pi-pi0 final state using a data sample of 78 fb-1 collected by the Belle detector at the KEKB e+e- collider. With no assumptions about intermediate states in the decay, the branching fraction is measured to be (36.6-4.3+4.2±3.0)×10-6. We also search for B decays to intermediate two-body states with the same K+pi-pi0
The masses of the neutral and charged D mesons have been measured with the KEDR detector at the V... more The masses of the neutral and charged D mesons have been measured with the KEDR detector at the VEPP-4M electron-positron collider: M D 0 = 1865.30 ± 0.33 ± 0.23 MeV, M D + = 1869.53 ± 0.49 ± 0.20 MeV. address: [email protected] (A.O. Poluektov). according to some models, is a bound state of D 0 and D * 0 mesons [5] and has a mass very close to the sum of the D 0 and D * 0 meson masses. Presently, the world-average D 0 mass value [6] (M D 0 = 1864.84 ± 0.17 MeV) is dominated by the CLEO measurement M D 0 = 1864.847 ± 0.150(stat) ± 0.095(syst) MeV [7]
We have searched for neutrinoless τ lepton decays into three charged leptons using an 87.1 fb −1 ... more We have searched for neutrinoless τ lepton decays into three charged leptons using an 87.1 fb −1 data sample collected with the Belle detector at the KEKB e + e − collider. Since the number of signal candidate events is compatible with that expected from the background, we set 90% confidence level upper limits on the branching fractions in the range (1.9-3.5) × 10 −7 for various decay modes τ − → − + − where represents e or µ. 2004 Published by Elsevier B.V.
We report the first observation of e;{+}e;{-}-->Upsilon(1S... more We report the first observation of e;{+}e;{-}-->Upsilon(1S)pi;{+}pi;{-}, Upsilon(2S)pi;{+}pi;{-}, and first evidence for e;{+}e;{-}-->Upsilon(3S)pi;{+}pi;{-}, Upsilon(1S)K+K-, near the peak of the Upsilon(5S) resonance at sqrt[s] approximately 10.87 GeV. The results are based on a data sample of 21.7 fb;{-1} collected with the Belle detector at the KEKB e;{+}e;{-} collider. Attributing the signals to the Upsilon(5S) resonance, the partial widths Gamma(Upsilon(5S)-->Upsilon(1S)pi;{+}pi;{-})=0.59+/-0.04(stat)+/-0.09(syst) MeV and Gamma(Upsilon(5S)-->Upsilon(2S)pi;{+}pi;{-})=0.85+/-0.07(stat)+/-0.16(syst) MeV are obtained from the observed cross sections. These values exceed by more than 2 orders of magnitude the previously measured partial widths for dipion transitions between lower Upsilon resonances.
The B meson decay modes B--&a... more The B meson decay modes B-->Dpp; and B-->D(*)pp; have been studied using 29.4 fb(-1) of data collected with the Belle detector at KEKB. The B;(0)-->D(0)pp; and B;(0)-->D(*0)pp; decays have been observed for the first time with branching fractions B(B;(0)-->D(0)pp;)=(1.18+/-0.15+/-0.16)x10(-4) and B(B;(0)-->D(*0)pp;)=(1.20(+0.33)(-0.29)+/-0.21)x10(-4). No signal has been found for the B+-->D(+)pp; and B+-->D(*+)pp; decay modes, and the corresponding upper limits at 90% C.L. are presented.
We report evidence for B(0) --> D(0)D(-) and the first observation... more We report evidence for B(0) --> D(0)D(-) and the first observation of the decay modes B(-) --> D(0)D(-) and B(-) --> D(0)D(*-) based on a sample of 152 x 10(6) BB events collected by the Belle detector at KEKB. The branching fractions for B(0) --> D(+) D(-), B--->D(0)D(-), and B--> D(0)D(*-) are found to be (1.91 +/- 0.51 +/- 0.30) x10(-4), (4.83 +/- 0.78 +/- 0.58) x 10(-4), and (4.57 +/- 0.71 +/- 0.56) x 10(-4), respectively. Charge asymmetries in the B---> D(0)D(-) and B(-) --> D(0)D(*-) channels are consistent with zero.
We present a search for the rare decays B --> h(*)nunu[over ], whe... more We present a search for the rare decays B --> h(*)nunu[over ], where h(*) stands for a light meson. A data sample of 535 x 10{6} BB[over ] pairs collected with the Belle detector at the KEKB e{+}e{-} collider is used. Signal candidates are required to have an accompanying B meson fully reconstructed in a hadronic mode and signal side particles consistent with a single h(*) meson. No significant signal is observed and we set upper limits on the branching fractions at 90% confidence level. The limits on B{0} --> K{*0}nunu[over ] and B{+} --> K{+}nunu[over ] decays are more stringent than the previous constraints, while the first searches for B{0} --> K{0}nunu[over ], pi{0}nunu[over ], rho{0}nunu[over ], varphinunu[over ] and B{+} --> K{*+}nunu[over ], rho{+}nunu[over ] are reported.
We report the first observation of a B meson decay that is not accessible by a direct spectator p... more We report the first observation of a B meson decay that is not accessible by a direct spectator process. The channel B(0)-->D(+)(s)K- is found in a sample of 85 x 10(6) BB; events, collected with the Belle detector at KEKB, with a branching fraction B(B(0)-->D(+)(s)K-)=(4.6(+1.2)(-1.1)+/-1.3) x 10(-5). We also obtain evidence for the B0-->D(+)(s)pi(-) decay with branching fraction B(B0-->D(+)(s)pi(-))=(2.4(+1.0)(-0.8)+/-0.7) x 10(-5). This value may be used to extract a model-dependent value of |V(ub)|.
We report the observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370), which are CP ei... more We report the observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370), which are CP eigenstate decay modes. These results are obtained from 121.4 fb⁻¹ of data collected at the Υ(5S) resonance with the Belle detector at the KEKB e(+)e⁻ collider. We measure the branching fractions B(B(s)⁰→J/ψf₀(980); f₀(980)→π(+)π⁻)=(1.16(-0.19)(+0.31)(stat)(-0.17)(+0.15)(syst)(-0.18)(+0.26)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 8.4σ, and B(B(s)⁰→J/ψf₀(1370); f₀(1370)→π(+)π⁻)=(0.34(-0.14)(+0.11)(stat)(-0.02)(+0.03)(syst)(-0.05)(+0.08)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 4.2σ. The last error listed is due to uncertainty in the number of produced B(s)((*))B(s)((*)) pairs.
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Papers by V. Aulchenko