4,106 research outputs found

    A Scintillating Fiber Hodoscope for a Bremstrahlung Luminosity Monitor at an Electron-Positron Collider

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    The performance of a scintillating fiber (2mm diameter) position sensitive detector (4.8×4.84.8 \times 4.8 cm2^2 active area) for the single bremstrahlung luminosity monitor at the VEPP-2M electron-positron collider in Novosibirsk, Russia is described. Custom electronics is triggered by coincident hits in the X and Y planes of 24 fibers each, and reduces 64 PMT signals to a 10 bit (X,Y) address. Hits are accumulated (10 kHz) in memory and display (few Hz) the VEPP-2M collision vertex. Fitting the strongly peaked distribution ( \sim 3-4 mm at 1.6m from the collision vertex of VEPP-2M ) to the expected QED angular distribution yields a background in agreement with an independent determination of the VEPP-2M luminosity.Comment: LaTeX with REVTeX style and options: multicol,aps. 8 pages, postscript figures separate from text. Accepted in Review of Scientific Instruments (~ Aug 1996

    Hadronic effects in leptonic systems: muonium hyperfine structure and anomalous magnetic moment of muon

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    Contributions of hadronic effects to the muonium physics and anomalous magnetic moment of muon are considered. Special attention is paid to higher-order effects and the uncertainty related to the hadronic contribution to the hyperfine structure interval in the ground state of muonium.Comment: Presented at PSAS 2002 (St. Petersburg

    τρππν\tau\to\rho\pi\pi\nu decays

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    Effective chiral theory of mesons is applied to study the four decay modes of τρππν\tau\to\rho\pi\pi\nu. Theoretical values of the branching ratios are in agreement with the data. The theory predicts that the a1a_{1} resonance plays a dominant role in these decays. There is no new parameter in this study.Comment: 12 pages and one figur
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