2,644 research outputs found

    The CLEO-III Ring Imaging Cherenkov Detector

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    The CLEO-III Detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented.Comment: Invited talk by R.J. Mountain at ``The 3rd International Workshop on Ring Imaging Cherenkov Detectors," a research workshop of the Israel Science Foundation, Ein-Gedi, Dead-Sea, Israel, Nov. 15-20, 1998, 14 pages, 9 figure

    The Cleo Rich Detector

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    We describe the design, construction and performance of a Ring Imaging Cherenkov Detector (RICH) constructed to identify charged particles in the CLEO experiment. Cherenkov radiation occurs in LiF crystals, both planar and ones with a novel ``sawtooth''-shaped exit surface. Photons in the wavelength interval 135--165 nm are detected using multi-wire chambers filled with a mixture of methane gas and triethylamine vapor. Excellent pion/kaon separation is demonstrated.Comment: 75 pages, 57 figures, (updated July 26, 2005 to reflect reviewers comments), to be published in NIM

    Flavor-Specific Inclusive B Decays to Charm

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    We have measured the branching fractions for B -> D_bar X, B -> D X, and B -> D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these results and some previously measured branching fractions, we obtain Br(b -> c c_bar s) = (21.9 ±\pm 3.7)%, Br(b -> s g) K^- \pi^+) = (3.69 ±\pm 0.20)%. Implications for the ``B semileptonic decay problem'' (measured branching fraction being below theoretical expectations) are discussed. The increase in the value of Br(b -> c c_bar s) due to B>DXB -> D X eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Further Search for the Two-Photon Production of the Glueball Candidate fJ(2220)f_{J}(2220)

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    The CLEOII detector at the Cornell e+ e- storage ring CESR has been used to search for the two-photon production of the fJ(2220)f_J(2220) decaying into pi+ pi-. No evidence for a signal is found in data corresponding to an integrated luminosity of 4.77/fb and a 95% CL upper limit on ΓtwophotonBRpi+pi\Gamma_{two-photon} * BR{pi+ pi-} of 2.5 eV is set. If this result is combined with the BES Collaboration's measurement of fJ(2220)>pi+pif_J(2220) -> pi+ pi- in radiative J/ψJ/\psi decay, a 95% CL lower limit on the stickiness of the fJ(2220)f_J(2220) of 73 is obtained. If the recent CLEO result for \Gamma_{two-photon} * BR{\K_S K_S} is combined with the present result, the stickiness of the fJ(2220)f_J(2220) is found to be larger than 102 at the 95% CL. These results for the stickiness (the ratio of the probabilities for two-gluon coupling and two-photon coupling) provide further support for a substantial neutral parton content in the fJ(2220)f_J(2220).Comment: 8 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of the Branching Ratios for the Decays of Ds+ηπ+,ηπ+,ηρ+D_{s}^{+}\to \eta\pi^{+}, \eta^{'}\pi^{+}, \eta\rho^{+}, and etaρ+eta^{'}\rho^{+}

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    Using a data sample with integrated luminosity of about 3.9 fb^{-1} collected in e+ e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds -> (eta, eta') pi and Ds -> (eta, eta') rho relative to Ds -> phi pi. These decay modes are among the most common hadronic decays of the Ds's and can be related by factorization to the semileptonic decays Ds -> (eta,eta') l nu. The results obtained are compared with previous CLEO results and with the branching ratios measured for the related semileptonic decays. We also report results on the Cabibbo-suppressed decays of the D+ to the same final states.Comment: 18 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Search for the Decay τ4pi3π+(π0)ντ\tau^{-}\to 4pi^{-}3\pi^{+}(\pi^{0})\nu_{\tau}

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    We have searched for the decay of the tau lepton into seven charged particles and zero or one pi0. The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 4.61 fb^(-1). No evidence for a signal is found. Assuming all the charged particles are pions, we set an upper limit on the branching fraction, B(tau- -> 4pi- 3pi+ (pi0) nu_tau) < 2.4 x 10^(-6) at the 90% confidence level. This limit represents a significant improvement over the previous limit.Comment: 9 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of the BˉDνˉ\bar{B}\to D\ell\bar{\nu} Partila Width and Form Factor Parameters

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    We have studied the decay BˉDνˉ\bar{B} \to D\ell\bar{\nu}, where =eorμ\ell=e or \mu. From a fit to the differential decay rate dΓ/dwd\Gamma/dw we measure the rate normalization FD(1)Vcb{\cal F}_D(1)|V_{cb}| and form factor slope ρ^D2\hat{\rho}^2_D, and, using measured values of τB\tau_B, find Γ(BˉDνˉ)=(12.0±0.9±2.1)ns1\Gamma(\bar{B} \to D\ell\bar{\nu}) = (12.0 \pm 0.9 \pm 2.1) ns^{-1}. The resulting branching fractions are B(Bˉ0D+νˉ)=(1.87±0.15±0.32){\cal B}(\bar{B}^0 \to D^+\ell^-\bar{\nu})=(1.87 \pm 0.15 \pm 0.32)% and B(BD0νˉ)=(1.94±0.15±0.34){\cal B}(B^- \to D^0\ell^-\bar{\nu})=(1.94 \pm 0.15 \pm 0.34)%. The form factor parameters are in agreement with those measured in BˉDνˉ\bar{B} \to D^*\ell\bar{\nu} decays, as predicted by heavy quark effective theory.Comment: 11 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN
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