4,291 research outputs found

    The Semileptonic Decay Fraction of B Mesons in the Light of Interfering Amplitudes

    Full text link
    Consequences of the interference between spectator amplitudes for the lifetimes and semileptonic decay fractions of B^0 and B^+ mesons are discussed. Assuming duality and constructive interference between spectator amplitudes we are able to explain the low experimental value for the semileptonic decay fraction of BB mesons. Extracting these amplitudes from a fit to 11 exclusive hadronic B decay fractions we find a_1 = 1.05 +/- 0.03 +/- 0.10, a_2 =+0.227 +/ 0.012 +/- 0.022, an inclusive semileptonic decay fraction of (11.2 +/- 0.5 +/- 1.7), and a lifetime ratio tau(B^+) / tau(B^0) = 0.83 +/- 0.01 +/- 0.01.Comment: 9 page

    The ARGUS Vertex Trigger

    Get PDF
    A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5\,mm radius.Comment: gzipped Postscript, 27 page

    Forward-backward and CP-violating asymmetries in rare B_{d,s}\to (V,\gamma) l^+l^- decays

    Full text link
    We study the forward-backward and the CP-violating asymmetries (both time-independent and time-dependent) in rare semileptonic Bdρ0l+lB_d\to\rho^0 l^+l^-, Bsϕl+lB_s\to\phi l^+l^-, and radiative leptonic Bd,sγl+lB_{d,s}\to \gamma l^+l^- decays and investigate the sensitivity of these asymmetries to the extensions of the Standard model.Comment: Revised version: plots for A_CP corrected, discussion of B_d\to \rho^0 l^+l^- adde

    Pengaruh Latihan Loncat Tali Terhadap Daya Tahan Dalam Permainan Badminton Pada Club Riau Televisi Pekanbaru

    Full text link
    The research problem is the Effect of jump rope exercises against resistance in the game of badminton at the club RTV pekanbaru. His goal to find out how much influence the relationship jump rope and endurance capabilities of individuals and groups. This research technique using total sampling with a sample of 10 athletes badminton RTV Pekanbaru. This study uses correlation techniques. Then, the test data using the normality test, the test product moment correlation, significant test α = 0:05. Normality test variable X, L0maks (0.2064) <Ltabel (0.258), and the normality test variable Y, L0maks (0.2015) <Ltabel (0.258) in other words 95% confidence level of normal data and conclusions of research shows: where there is a significant relationship between the effect of jump rope and endurance capabilities, Similarly, Ho is rejected and Ha accepted

    Penghilangan Mikroorganisme Dalam Air Minum Dengan Dielectric Barrier Discharge

    Full text link
    Microorganisms such as Escherichia coli in water are a component that is difficult to remove in conventional water treatment systems. Several systems have been implemented to reduce levels of microorganisms is the use of disinfectants, the membrane filtration and activated carbon absorption. These systems have several weaknesses, so that not all microorganisms can be removed from drinking water. The plasma system is an applicable technology for removing organic compounds and microorganisms in drinking water. By creating plasma in water will produce several of active species such as OH-, H+, O3 and H2O2 that has a high oxidation potential, decompose organic compounds and kill microorganisms in the water significantly. This paper will describe the removal of microorganisms in drinking water using a plasma system by the method of dielectric barrier discharge (DBD ). The results howed that the pH of drinking water produced in the range 6.5 to 7.3. The higher voltage causes the higher the conductivity, temperature and ORP water. Removal efficiency for the content of microorganisms Coli Fecal and Coliform in the range 99.2 to 100% after water was injected voltage of 13-17 kV for 10 minutes

    Measurement of exclusive production of scalar χc0\chi_{c0} meson in proton-(anti)proton collisions via χc0π+π\chi_{c0} \to \pi^{+}\pi^{-} decay

    Full text link
    We consider a measurement of exclusive production of scalar χc(0++)\chi_{c}(0^{++}) meson in the proton-proton collisions at LHC and RHIC and in the proton-antiproton collisions at the Tevatron via χc0π+π\chi_{c0} \to \pi^{+}\pi^{-} decay. The corresponding amplitude for exclusive double-diffractive χc0\chi_{c0} meson production was obtained within the ktk_{t}-factorization approach including virtualities of active gluons and the corresponding cross section is calculated with unintegrated gluon distribution functions (UGDFs) known from the literature. The four-body ppppπ+πp p \to p p \pi^+ \pi^- reaction constitutes an irreducible background to the exclusive χc0\chi_{c0} meson production. We calculate several differential distributions for pp(pˉ)pp(pˉ)χc0pp(\bar{p}) \to pp(\bar{p})\chi_{c0} process including absorptive corrections. The influence of kinematical cuts on the signal-to-background ratio is investigated. Corresponding experimental consequences are discussed.Comment: 16 pages, 10 figures, 2 table

    Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags

    Full text link
    Using the ARGUS detector at the e+ee^+ e^- storage ring DORIS II, we have measured the Michel parameters ρ\rho, ξ\xi, and ξδ\xi\delta for τ±l±ννˉ\tau^{\pm}\to l^{\pm} \nu\bar\nu decays in τ\tau-pair events produced at center of mass energies in the region of the Υ\Upsilon resonances. Using τρν\tau^\mp \to \rho^\mp \nu as spin analyzing tags, we find ρe=0.68±0.04±0.08\rho_{e}=0.68\pm 0.04 \pm 0.08, ξe=1.12±0.20±0.09\xi_{e}= 1.12 \pm 0.20 \pm 0.09, ξδe=0.57±0.14±0.07\xi\delta_{e}= 0.57 \pm 0.14 \pm 0.07, ρμ=0.69±0.06±0.08\rho_{\mu}= 0.69 \pm 0.06 \pm 0.08, ξμ=1.25±0.27±0.14\xi_{\mu}= 1.25 \pm 0.27 \pm 0.14 and ξδμ=0.72±0.18±0.10\xi\delta_{\mu}= 0.72 \pm 0.18 \pm 0.10. In addition, we report the combined ARGUS results on ρ\rho, ξ\xi, and ξδ\xi\delta using this work und previous measurements.Comment: 10 pages, well formatted postscript can be found at http://pktw06.phy.tu-dresden.de/iktp/pub/desy97-194.p

    Application of Al-Cu-W-Ta graded density impactors in dynamic ramp compression experiments

    Get PDF
    Graded density impactors (GDIs) are used to dynamically compress materials to extreme conditions. Two modifications to a previously developed Mg-Cu-W GDI are made in this work before using it in a dynamic compression experiment: Mg is replaced with Al and a Ta disk is glued to the back. The Mg phase is replaced by Al because FCC Al remains solid to higher pressure along its Hugoniot compared to Mg. The addition of the Ta disk creates a constant particle velocity regime and facilitates a definition of peak pressure states. Microstructure analysis, profilometry, and ultrasonic C-scans of the Al-Cu-W GDI all confirm excellent uniformity. We evaluated signal variation in the radial direction of a dynamically compressed Al-LiF bilayer target to evaluate the contribution of spatial nonuniformity to errors. Velocity traces from five photon Doppler velocimetry (PDV) probes located at different radial distances from the center of the target varied at most by 1.1% with a root mean square of 0.3% during the compression ramp, demonstrating low PDV measurement error over a relatively large experimental area. The experimental PDV data also agrees well with 1D simulations that use inputs from predictive characterization models developed for the material properties resulting from tape casting, laminating, and powder consolidation processes. Low measurement error during quasi-isentropic compression, leading to better precision, ensures a robust platform to reach extreme compression and low-temperature recovery states and facilitates discovery via synthesis, quenching, and preservation of new high-pressure phases

    Application of Al-Cu-W-Ta graded density impactors in dynamic ramp compression experiments

    Get PDF
    Graded density impactors (GDIs) are used to dynamically compress materials to extreme conditions. Two modifications to a previously developed Mg-Cu-W GDI are made in this work before using it in a dynamic compression experiment: Mg is replaced with Al and a Ta disk is glued to the back. The Mg phase is replaced by Al because FCC Al remains solid to higher pressure along its Hugoniot compared to Mg. The addition of the Ta disk creates a constant particle velocity regime and facilitates a definition of peak pressure states. Microstructure analysis, profilometry, and ultrasonic C-scans of the Al-Cu-W GDI all confirm excellent uniformity. We evaluated signal variation in the radial direction of a dynamically compressed Al-LiF bilayer target to evaluate the contribution of spatial nonuniformity to errors. Velocity traces from five photon Doppler velocimetry (PDV) probes located at different radial distances from the center of the target varied at most by 1.1% with a root mean square of 0.3% during the compression ramp, demonstrating low PDV measurement error over a relatively large experimental area. The experimental PDV data also agrees well with 1D simulations that use inputs from predictive characterization models developed for the material properties resulting from tape casting, laminating, and powder consolidation processes. Low measurement error during quasi-isentropic compression, leading to better precision, ensures a robust platform to reach extreme compression and low-temperature recovery states and facilitates discovery via synthesis, quenching, and preservation of new high-pressure phases
    corecore