1,360 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

    QCD-based description of one-particle inclusive B decays

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    We discuss one-particle inclusive B decays in the limit of heavy b and c quarks. Using the large-N_C limit we factorize the non-leptonic matrix elements, and we employ a short distance expansion. Modeling the remaining nonperturbative matrix elements we obtain predictions for various decay channels and compare them with existing data.Comment: LaTeX, 22 pages, 6 figures (eps); analytical and numerical results unchanged, misrepresentation of experimental data in Fig. 5 corrected, final published versio

    Heavy Baryon Production and Decay

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    The branching ratio B(Lambda_c -> p K- pi+) normalizes the production and decay of charmed and bottom baryons. At present, this crucial branching ratio is extracted dominantly from B.bar -> baryons analyses. This note questions several of the underlying assumptions and predicts sizable B.bar -> D(*) N N'.bar X transitions, which were traditionally neglected. It predicts B(Lambda_c -> p K- pi+) to be significantly larger (0.07 +/- 0.02) than the world average. Some consequences are briefly mentioned. Several techniques to measure B(Lambda_c -> p K- pi+) are outlined with existing or soon available data samples. By equating two recent CLEO results, an appendix obtains B(D0 -> K- pi+)= 0.035 +/- 0.002, which is somewhat smaller than the current world average.Comment: 27 pages, 4 eps figures, revte

    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

    Potential Models for Radiative Rare B Decays

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    We compute the branching ratios for the radiative rare decays of B into K-Meson states and compare them to the experimentally determined branching ratio for inclusive decay b -> s gamma using non relativistic quark model, and form factor definitions consistent with HQET covariant trace formalism. Such calculations necessarily involve a potential model. In order to test the sensitivity of calculations to potential models we have used three different potentials, namely linear potential, screening confining potential and heavy quark potential as it stands in QCD.We find the branching ratios relative to the inclusive b ->s gamma decay to be (16.07\pm 5.2)% for B -> K^* (892)gamma and (7.25\pm 3.2)% for B -> K_2^* (1430)gamma for linear potential. In the case of the screening confining potential these values are (19.75\pm 5.3)% and (4.74\pm 1.2)% while those for the heavy quark potential are (11.18\pm 4.6)% and (5.09\pm 2.7)% respectively. All these values are consistent with the corresponding present CLEO experimental values: (16.25\pm 1.21)% and (5.93\pm 0.46)%.Comment: RevTeX, 6 pages, 1 eps figur

    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

    Performance of the CLEO III LiF-TEA Ring Imaging Cherenkov Detector in a High Energy Muon Beam

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    The CLEO III Ring Imaging Cherenkov detector uses LiF radiators to generate Cherenkov photons which are then detected by proportional wire chambers using a mixture of CH4_4 and TEA gases. The first two photon detector modules which were constructed, were taken to Fermilab and tested in a beam dump that provided high momentum muons. We report on results using both plane and "sawtooth" shaped radiators. Specifically, we discuss the number of photoelectrons observed per ring and the angular resolution. The particle separation ability is shown to be sufficient for the physics of CLEO III

    Motivation and Motor Control: Hemispheric Specialization for Approach Motivation Reverses with Handedness

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    (SSH), according to which the hemispheric laterality of affective motivation depends on the laterality of motor control for the dominant hand (i.e., the “sword hand," used preferentially to perform approach actions) and the nondominant hand (i.e., the “shield hand," used preferentially to perform avoidance actions).To determine whether the laterality of approach motivation varies with handedness, we measured alpha-band power (an inverse index of neural activity) in right- and left-handers during resting-state electroencephalography and analyzed hemispheric alpha-power asymmetries as a function of the participants' trait approach motivational tendencies. Stronger approach motivation was associated with more left-hemisphere activity in right-handers, but with more right-hemisphere activity in left-handers.The hemispheric correlates of approach motivation reversed between right- and left-handers, consistent with the way they typically use their dominant and nondominant hands to perform approach and avoidance actions. In both right- and left-handers, approach motivation was lateralized to the same hemisphere that controls the dominant hand. This covariation between neural systems for action and emotion provides initial support for the SSH

    Measuring β\beta in BD+DKsB \to D^{*+}D^{*-}K_s Decays

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    We consider the possibility of measuring both sin(2β)\sin (2 \beta) and cos(2β)\cos (2 \beta) in the KM unitarity triangle using the process B0D+DKsB^0 \to D^{*+}D^{*-}K_s. This decay mode has a higher branching fraction (O(1%)) than the mode B0D+DB^0 \to D^{*+}D^{*-}. We use the factorization assumption and heavy hadron chiral perturbation theory to estimate the branching fraction and polarization. The time dependent rate for B0(t)D+DKsB^0(t) \to D^{*+} D^{*-} K_s can be used to measure sin(2β)\sin (2 \beta) and cos(2β)\cos(2 \beta) . Furthermore, examination of the D+KsD^{*+} K_s mass spectrum may be the best way to experimentally find the broad 1+1^+ p-wave DsD_s meson.Comment: Revtex, 28 pages, 7 figures, title changed, introduction expanded, added references, details of calculations moved to the appendi
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