162 research outputs found

    New Measurements of Upsilon(1S) Decays to Charmonium Final States

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    Using substantially larger data samples collected by the CLEO III detector, we report on new measurements of the decays of Upsilon(1S) to charmonium final states, including J/Psi, psi(2S), and chi_cJ. The latter two are first observations of these decays. We measure the branching fractions as follows: B(Y(1S)--> J/Psi+X)=(6.4+-0.4+-0.6)x10^-4, B(Y(1S)--> psi(2S)+X)/B(Y(1S)--> J/Psi+X)=0.41+-0.11+-0.08, B(Y(1S)--> chi_c1+X)/B(Y(1S)--> J/Psi+X)=0.35+-0.08+-0.06, B(Y(1S)--> chi_c2+X)/B(Y(1S)--> J/Psi+X)=0.52+-0.12+-0.09, and B(Y(1S)--> chi_c0+X)/B(Y(1S)--> J/Psi+X)<7.4% at 90% confidence level. We also report on the momentum and angular spectra of J/Psi's in Upsilon(1S) decay. The results are compared to predictions of the color octet and color singlet models.Comment: 27 pages postscript,also available through http://w4.lns.cornell.edu/public/CLNS/, submitted to PR

    Moments of the B Meson Inclusive Semileptonic Decay Rate using Neutrino Reconstruction

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    We present a measurement of the composition of B meson inclusive semileptonic decays using 9.4 fb^-1 of e^+e^- data taken with the CLEO detector at the Upsilon(4S) resonance. In addition to measuring the charged lepton kinematics, the neutrino four-vector is inferred using the hermiticity of the detector. We perform a maximum likelihood fit over the full three-dimensional differential decay distribution for the fractional contributions from the B -> X_c l nu processes with X_c = D, D*, D**, and nonresonant X_c, and the process B -> X_u l nu. From the fit results we extract the first and second moments of the M_X^2 and q^2 distributions with minimum lepton-energy requirements of 1.0 GeV and 1.5 GeV. We find = 0.456 +- 0.014 +- 0.045 +- 0.109 (GeV/c^2)^2 with a minimum lepton energy of 1.0 GeV and = 0.293 +- 0.012 +- 0.033 +- 0.048 (GeV/c^2)^2 with minimum lepton energy of 1.5 GeV. The uncertainties are from statistics, detector systematic effects, and model dependence, respectively. As a test of the HQET and OPE calculations, the results for the M^X_c moment as a function of the minimum lepton energy requirement are compared to the predictions.Comment: 26 pages postscript, als available through http://w4.lns.cornell.edu/public/CLNS/, Submitted to PRD (back-to-back with following preprint hep-ex/0403053

    Photon transitions in Upsilon(2S) and Upsilon(3S)

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    We have studied the inclusive photon spectra in Upsilon(2S) and \Upsilon(3S) decays using a large statistics data sample obtained with the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates and photon energies for Upsilon(2S)->gamma chi_bJ(1P) and Upsilon(3S)->gamma chi_bJ(2P) J=0,1,2. We measure the rate for a rare E1 transition Upsilon(3S)->gamma chi_b0(1P) for the first time. We also set upper limits on the rates for the hindered magnetic dipole (M1) transitions to the eta_b(1S) and eta_b(2S) states.Comment: 10 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR

    Measurement of \cal{B}(D^+ --> mu^+ nu) and the Pseudoscalar Decay Constant fD+f_{D^+}

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    In 60 pb-1 of data taken on the psi(3770) resonance with the CLEO-c detector, we find 8 D+ to mu+ nu event candidates that are mostly signal, containing only 1 estimated background. Using this statistically compelling sample, we measure preliminary values of B(D+ to mu+ nu) = (3.5 +- 1.4 +- 0.6)*10^{-4}, and determine f_{D+} =(201+- 41+- 17) MeV.Comment: 17 pages postscript, also available through http://www.lns.cornell.edu/public/CONF/2004/, Presented at ICHEP Aug 16-22,2004, Beijing, Chin

    Search for X(3872) in gamma gamma Fusion and ISR at CLEO

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    We report on a search for the recently reported X(3872) state using 15.1 fb^{-1} e+ e- data taken in the \sqrt{s} = 9.46-11.30 GeV region. Separate searches for the production of X(3872) in untagged gamma-gamma fusion and e+ e- annihilation following initial state radiation (ISR) are made by taking advantage of the unique correlation of J/psi -> l+ l- in X(3872) decay to pi+ pi- J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)\Gamma_{\gamma\gamma}B(X -> pi+ pi- J/psi) < 12.9 eV and \Gamma_{ee}B(X -> pi+ pi- J/psi) < 8.3 eV.Comment: 8 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR

    Study of tau Decays to Four-Hadron Final States with Kaons

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    The tau decays to four hadrons have been studied with the CLEO III detector at the Cornell Electron Storage Ring (CESR) using (7.56 +- 0.15) fb^{-1} of data collected near the Y(4S) resonance. We present the first statistically significant measurements of B(tau- -> K- pi+pi- pi0 nu, excluding K^0) = (7.4 +- 0.8 +- 1.1) x 10^{-4} and B(tau--> K- K+ pi- pi0 nu) = (5.5 +- 1.4 +- 1.2) x 10^{-5}, including the first observation of the decay, tau- -> K- omega nu, with branching fraction (4.1 +- 0.6 +- 0.7) x 10^{-4}. We also publish the first upper limit for B(tau- -> K- K+ K- pi0 nu) < 4.8 (6.1) x 10^{-6} at 90% (95%) confidence level (C.L.).Comment: 9 pages postscript, also available from http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR

    The Search for eta(1440) --> K^0_S K^pm \pi^mp in Two-Photon Fusion at CLEO

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    We analyze 13.8 \rm fb^{-1} of the integrated e^+e^- luminosity collected at 10.6 GeV center-of-mass energy with the CLEO II and CLEO II.V detectors to study exclusive two-photon production of hadrons with masses below 1.7{\rm \ GeV/c^2} decaying into the K^0_S K^\pm \pi^\mp final state. We observe two statistically significant enhancements in the \eta(1440) mass region. These enhancements have large transverse momentum which rules them out as being due to pseudoscalar resonances but is consistent with the production of axial-vector mesons. We use tagged two-photon events to study the properties of the observed enhancements and associate them with the production of f_1(1285) and f_1(1420). Our non-observation of \eta(1440) is inconsistent by more than two standard deviations with the first observation of this resonance in two-photon collisions by the L3 experiment. We present our estimates for 90% confidence level upper limits on the products of two-photon partial widths of pseudoscalar hadrons and their branching fractions into K^0_S(\pi^+\pi^-)K^\pm\pi^\mp.Comment: 24 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR

    Absolute Branching Fraction Measurements of Exclusive D^0 Semileptonic Decays

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    With the first data sample collected by the CLEO-c detector at the psi(3770) resonance we have studied four exclusive semileptonic decays of the D0 meson. Our results include the first observation and absolute branching fraction measurement for D0 --> rho- e+ nu_e and improved measurements of the absolute branching fractions for D0 decays to K- e+ nu_e, pi- e+ nu_e, and K*- e+ nu_e.Comment: 9 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2005/, submitted to PR

    Measurement of Absolute Hadronic Branching Fractions of D Mesons and e^+e^- --> D barD Cross Sections at E_cm = 3773 MeV

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    Using 55.8 pb^-1 of e^+e^- collisions recorded at the psi(3770) resonance with the CLEO-c detector at CESR, we determine absolute hadronic branching fractions of charged and neutral D mesons using a double tag technique. Among measurements for three D^0 and six D^+ modes, we obtain reference branching fractions B(D^0 -> K^- pi^+)=(3.91 +- 0.08 +- 0.09)% and B(D^+ -> K^- pi^+ pi^+)=(9.5 +- 0.2 +- 0.3)%, where the uncertainties are statistical and systematic, respectively. Final state radiation is included in these branching fractions by allowing for additional, unobserved, photons in the final state. Using a determination of the integrated luminosity, we also extract the cross sections sigma(e^+e^- -> D^0 \bar D^0)=(3.60 +- 0.07 +0.07-0.05) nb and sigma(e^+e^- -> D^+D^-)=(2.79 +- 0.07 +0.10-0.04) nb.Comment: 9 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2005/, submitted to PR
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