30 research outputs found

    CP Violation via ρω\rho \omega Interference

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    We consider B±,0ρ0(ω)h±,0B^{\pm,0} \to \rho^0(\omega)h^{\pm,0}, where ρ0(ω)\rho^0(\omega) decays to π+π\pi^+\pi^- and hh is any hadronic final state, such as π\pi or KK. We find a large direct CP asymmetry in B-meson decays via ρω\rho \omega interference. A possible method to determine weak phases, such as ϕ2,3\phi_{2,3}, is discussed. The experimental feasibility is also shown.Comment: 7 pages, latex(sprocl.sty included), 2 figures. Talk presented at "Int. Conf. on B-physics and CP violation" Hawaii 9

    Test of Various Photocathodes

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    A test of various photocathodes was carried out. The tested materials were CsI, CsTe, their multi-layers and so on. The quantum efficiencies of the various materials were measured under a vacuum and/or after exposure to several kinds of gases.Comment: 7 pages, Latex format(article), figures included, published in NIM A343(1994)11

    Electron identification using the TOPAZ detector at TRISTAN

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    We present an electron-identification method using the time-projection chamber and the lead-glass calorimeter in the TOPAZ detector system. Using this method we have achieved good electron identification against hadron backgrounds over a wide momentum range in the hadronic events produced by both single-photon exchange and two-photon processes. Pion-rejection factors and electron efficiencies were 163 and 68.4\% for high-PTP_T electrons and 137 and 42.7\% for low-PTP_T electrons in the single-photon-exchange process, and 8600 and 36.0\% for the two-photon process, respectively.Comment: 32 pages, latex format (article), 24 figures, submitted for publication

    Direct CP violation in three-body decays of the BB meson by resonance effects

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    We discuss direct CP violation in three-body decays of BB meson such as B±K±π+πB^\pm \to K^\pm\pi^+\pi^-, which involves various intermediate resonance states, such as B±Kiπ±B^\pm \to K^*_i \pi^\pm and B±ρK±B^\pm \to \rho K^\pm, where KiK^*_i represents the πK\pi K resonance. Due to the large final state interaction phases of the resonances, the CP asymmetry can be as large as the 25% level near the kinematical region where the KiK^*_i and ρ\rho resonances overlap. By examining a Dalitz plot of this mode and combining a measurement of the branching ratio for B±ρ±KB^\pm \to \rho^\pm K, it is possible to extract the weak phase, ϕ3\phi_3= arg(VudVub/(VcdVcb))(-V_{ud}V_{ub}^*/(V_{cd}V_{cb}^*)), of the Kobayashi-Maskawa matrix.Comment: 12 pages, 1 figures. Argument to determine the CKM angle is changed. Also available via anonymous ftp at ftp://ftp.kek.jp/kek/preprints/TH/TH-54

    Development of an atmospheric Cherenkov imaging camera for the CANGAROO-III experiment

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    A Cherenkov imaging camera for the CANGAROO-III experiment has been developed for observations of gamma-ray induced air-showers at energies from 1011^{11} to 1014^{14} eV. The camera consists of 427 pixels, arranged in a hexagonal shape at 0.17^\circ intervals, each of which is a 3/4-inch diameter photomultiplier module with a Winston-cone--shaped light guide. The camera was designed to have a large dynamic range of signal linearity, a wider field of view, and an improvement in photon collection efficiency compared with the CANGAROO-II camera. The camera, and a number of the calibration experiments made to test its performance, are described in detail in this paper.Comment: 25 pages, 29 figures, elsart.cls, to appear in NIM-

    IMAGING ATMOSPHERIC CHERENKOV TELESCOPE

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    The principle of Air Čherenkov techniques used to detect very high-energy astronomical gamma-rays is presented.The CANGAROO experiment in the southern hemisphere as well as other experiments in the world are introduced. The results of past and present experiments are briefly reviewed and also future prospects of this technique are mentioned.
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