502 research outputs found

    The effect of CDC recommended disinfecting solutions on Goldmann tonometer biprisms

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    Twelve new Goldmann biprisms were used to measure the intraocular pressure of the right eye of a single subject four times each day for fifteen days. Between measurements, nine of these biprisms were disinfected in the three solutions recommended by the Centers for Disease Control (CDC) as effective against the AIDS virus. The remaining three biprisms were disinfected by rubbing the biprism face with an isopropyl alcohol swab, a standard procedure in many clinical settings. The intraocular pressure measurements obtained using the four disinfecting regimens were compared to determine if any of the regimens influenced the results. At the time of measurement each biprism was evaluated to determine if any of the regimens affected the clarity of its front surface or the image of the Goldmann rings seen when performing the measurement. When comparing the clarity of the biprisms, those soaked in alcohol were found to be significantly different from all other groups, with all of the alcohol soaked biprisms being unusable after the fourth day. None of the other three disinfecting groups differed significantly from each other in regard to biprism clarity. Because the biprisms soaked in alcohol were unusable so early in the study, they were not used in the statistical analyses of lOP measurement and biprism image quality. No clinically significant difference was found in intraocular pressure measurements obtained with the three remaining disinfecting regimens of hydrogen peroxide, bleach and alcohol swab. When comparing the image seen while performing the Goldmann measurement, a significant difference was found between the hydrogen peroxide treated biprisms and those treated with bleach or the alcohol swab, with the hydrogen peroxide treated biprisms showing less image distortion. These results suggest that of the three disinfecting reigmens approved by CDC, hydrogen peroxide is the disinfecting agent of choice for the Goldmann biprism

    Observation of the Dynamic Beta Effect at CESR with CLEO

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    Using the silicon strip detector of the CLEO experiment operating at the Cornell Electron-positron Storage Ring (CESR), we have observed that the horizontal size of the luminous region decreases in the presence of the beam-beam interaction from what is expected without the beam-beam interaction. The dependence on the bunch current agrees with the prediction of the dynamic beta effect. This is the first direct observation of the effect.Comment: 9 page uuencoded postscript file, postscritp file also available through http://w4.lns.cornell.edu/public/CLNS, submitted to Phys. Rev.

    Rare radiative B decays to orbitally excited K mesons

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    The exclusive rare radiative B meson decays to orbitally excited axial-vector mesons K_1^*(1270), K_1(1400) and to the tensor meson K_2^*(1430) are investigated in the framework of the relativistic quark model based on the quasipotential approach in quantum field theory. These decays are considered without employing the heavy quark expansion for the s quark. Instead the s quark is treated to be light and the expansion in inverse powers of the large recoil momentum of the final K^{**} meson is used to simplify calculations. It is found that the ratio of the branching fractions of rare radiative B decays to axial vector K^*_1(1270) and K_1(1400) mesons is significantly influenced by relativistic effects. The obtained results for B decays to the tensor meson K_2^*(1430) agree with recent experimental data from CLEO.Comment: 17 pages, revte

    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

    Study of Charmless Hadronic B Meson Decays to Pseudoscalar-Vector Final States

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    We report results of searches for charmless hadronic B meson decays to pseudoscalar(pi^+-,K^+-,Pi^0 or Ks^0)-vector(Rho, K* or Omega) final states. Using 9.7 million BBbar pairs collected with the CLEO detector, we report first observation of B^- --> Pi^-Rho^0, B^0 --> Pi^+-Rho^-+ and B^- --> Pi^-Omega, which are expected to be dominated by hadronic b --> u transitions. The measured branching fractions are (10.4+3.3-3.4+-2.1)x10^-6, (27.6+8.4-7.4+-4.2)x10^-6 and (11.3+3.3-2.9+-1.4)x10^-6, respectively. Branching fraction upper limits are set for all the other decay modes investigated.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Study of 3-prong Hadronic τ\tau Decays with Charged Kaons

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    Using a sample of 4.7/fb integrated luminosity accumulated with the CLEO-II detector at the Cornell Electron Storage Ring (CESR), we have measured the branching fractions of the tau lepton into Kh+πντK^- h^+ \pi^- \nu_\tau and KK+πντK^- K^+ \pi^- \nu_\tau relative to hh+hντ;Kh+ππ0ντh^- h^+ h^- \nu_\tau; K^- h^+ \pi^- \pi^0\nu_\tau and KK+ππ0ντK^- K^+ \pi^- \pi^0\nu_\tau relative to hh+hπ0ντh^- h^+ h^- \pi^0 \nu_\tau. The relative branching fractions are: (5.16+-0.20+-0.50)*10210^{-2}, (1.52+-0.14+-0.29)*10210^{-2}, (2.54+-0.44+-0.39)*10210^{-2} and <0.0154<0.0154 at 95% C.L., respectively. Coupled with additional experimental information, we use our results to extract information on the structure of three-prong tau decays to charged kaons.Comment: 16 pages postscript file also available through http://w4.lns.cornell.edu/public/CLN

    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
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