503 research outputs found

    Scalar and Tensor Couplings in Kaon Decays

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    In the past few years charged kaon experiments have indicated possible scalar and tensor couplings in semileptonic kaon decays(K --> pi e nu). These couplings, if correct, are not predicted by the Standard Model and may indicate the onset of new physics. We present a summary of the existing data and a new, precision measurement of these couplings in the neutral kaon system based on a 3% subset of the data taken by the KTeV (E799) experiment at Fermilab

    Channeling and Volume Reflection Based Crystal Collimation of Tevatron Circulating Beam Halo (T-980)

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    The T980 crystal collimation experiment is underway at the Tevatron to determine if this technique could increase 980 GeV beam-halo collimation efficiency at high-energy hadron colliders such as the Tevatron and the LHC. T980 also studies various crystal types and parameters. The setup has been substantially enhanced during the Summer 2009 shutdown by installing a new O-shaped crystal in the horizontal goniometer, as well as adding a vertical goniometer with two alternating crystals (O-shaped and multi-strip) and additional beam diagnostics. First measurements with the new system are quite encouraging, with channeled and volume-reflected beams observed on the secondary collimators as predicted. Investigation of crystal collimation efficiencies with crystals in volume reflection and channeling modes are described in comparison with an amorphous primary collimator. Results on the system performance are presented for the end-of-store studies and for entire collider stores. The first investigation of colliding beam collimation simultaneously using crystals in both the vertical and horizontal plane has been made in the regime with horizontally channeled and vertically volume-reflected beams. Planning is underway for significant hardware improvements during the FY10 summer shutdown and for dedicated studies during the final year of Tevatron operation and also for a "post-collider beam physics running" period.Comment: 3 pp. 1st International Particle Accelerator Conference: IPAC'10, 23-28 May 2010: Kyoto, Japa

    The NOvA power distribution system

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    We describe the power distribution systems and grounding schemes built for the near and far detectors of the NOvA long-baseline neutrino experiment. They are used to power the avalanche photodiodes and their thermoelectric coolers, the front-end boards that read out, digitize and time stamp the signals from the avalanche photodiodes, and the data concentrator modules used to receive and format the data from the front-end boards before sending them to a farm of computers used to build the events. The system powers 344, 064 readout channels in the far detector and 20, 192 channels in the near detector

    Beam Condition Monitoring with Diamonds at CDF

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    This report talks Beam Condition Monitoring with Diamonds at CD

    Averages of bb-hadron, cc-hadron, and τ\tau-lepton properties as of summer 2014

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    This article reports world averages of measurements of bb-hadron, cc-hadron, and τ\tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through summer 2014. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CPCP violation parameters, parameters of semileptonic decays and CKM matrix elements.Comment: 436 pages, many figures and tables. Online updates available at http://www.slac.stanford.edu/xorg/hfag
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