87,705 research outputs found

    Fitting Precision Electroweak Data with Exotic Heavy Quarks

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    The 1999 precision electroweak data from LEP and SLC persist in showing some slight discrepancies from the assumed standard model, mostly regarding bb and cc quarks. We show how their mixing with exotic heavy quarks could result in a more consistent fit of all the data, including two unconventional interpretations of the top quark.Comment: 7 pages, no figure, 2 typos corrected, 1 reference update

    Theoretical and experimental investigation on modulation-inducing retrodirective optical systems /miros/ monthly progress report, 20 dec. 1964 - 20 jan. 1965

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    Modulation inducing retrodirecting optical system - diode mount for gallium arsenide lasers, and generation of alkaline line by stimulated Raman emissio

    Systolic VLSI for Kalman filters

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    A novel two-dimensional parallel computing method for real-time Kalman filtering is presented. The mathematical formulation of a Kalman filter algorithm is rearranged to be the type of Faddeev algorithm for generalizing signal processing. The data flow mapping from the Faddeev algorithm to a two-dimensional concurrent computing structure is developed. The architecture of the resulting processor cells is regular, simple, expandable, and therefore naturally suitable for VLSI chip implementation. The computing methodology and the two-dimensional systolic arrays are useful for Kalman filter applications as well as other matrix/vector based algebraic computations

    The BcB_c Decays to PP-wave Charmonium by Improved Bethe-Salpeter Approach

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    We re-calculate the exclusive semileptonic and nonleptonic decays of BcB_c meson to a PP-wave charmonium in terms of the improved Bethe-Salpeter (B-S) approach, which is developed recently. Here the widths for the exclusive semileptonic and nonleptonic decays, the form factors, and the charged lepton spectrums for the semileptonic decays are precisely calculated. To test the concerned approach by comparing with experimental measurements when the experimental data are available, and to have comparisons with the other approaches the results obtained by the approach and those by some approaches else as well as the original B-S approach, which appeared in literature, are comparatively presented and discussed.Comment: 33 pages, 5 figures, 3 table

    Shifting RbR_b with AFBbA^b_{FB}

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    Precision measurements at the ZZ resonance agree well with the standard model. However, there is still a hint of a discrepancy, not so much in RbR_b by itself (which has received a great deal of attention in the past several years) but in the forward-backward asymmetry AFBbA^b_{FB} together with RbR_b. The two are of course correlated. We explore the possibilty that these and other effects are due to the mixing of bLb_L and bRb_R with one or more heavy quarks.Comment: 11 pages, 1 Figure, LaTex fil

    Estimating Form Factors of Bs→Ds(∗)B_s\rightarrow D_s^{(*)} and their Applications to Semi-leptonic and Non-leptonic Decays

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    Bs0→Ds−B_s^0\rightarrow D_s^{-} and Bs0→Ds∗−B_s^0\rightarrow D_s^{*-} weak transition form factors are estimated for the whole physical region with a method based on an instantaneous approximated Mandelstam formulation of transition matrix elements and the instantaneous Bethe-Salpeter equation. We apply the estimated form factors to branching ratios, CP asymmetries and polarization fractions of non-leptonic decays within the factorization approximation. And we study the non-factorizable effects and annihilation contributions with the perturbative QCD approach. The branching ratios of semi-leptonic Bs0→Ds(∗)−l+νlB_s^0\rightarrow D_s^{(*)-}l^+\nu_l decays are also evaluated. We show that the calculated decay rates agree well with the available experimental data. The longitudinal polarization fraction of Bs→Ds∗V(A)B_s\rightarrow D_s^*V(A) decays are ∼0.8\sim0.8 when V(A)V(A) denotes a light meson, and are ∼0.5\sim0.5 when V(A)V(A) denotes a DqD_q (q=d,sq=d,s) meson.Comment: Final version published in J Phys. G 39 (2012) 045002 (Title also changed
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