2,943 research outputs found

    The International Linear Collider beam dumps

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    The ILC beam dumps are a key part of the accelerator design. At Snowmass 2005, the current status of the beam dump designs were reviewed, and the options for the overall dump layout considered. This paper describes the available dump options for the baseline and the alternatives and considers issues for the dumps that require resolution.Comment: Prepared for 2005 International Linear Collider Physics and Detector Workshop and 2nd ILC Accelerator Workshop, Snowmass, Colorado, 14-27 Aug 200

    Precision Measurements of Higgs Couplings: Implications for New Physics Scales

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    The measured properties of the recently discovered Higgs boson are in good agreement with predictions from the Standard Model. However, small deviations in the Higgs couplings may manifest themselves once the currently large uncertainties will be improved as part of the LHC program and at a future Higgs factory. We review typical new physics scenarios that lead to observable modifications of the Higgs interactions. They can be divided into two broad categories: mixing effects as in portal models or extended Higgs sectors, and vertex loop effects from new matter or gauge fields. In each model we relate coupling deviations to their effective new physics scale. It turns out that with percent level precision the Higgs couplings will be sensitive to the multi-TeV regime.Comment: Invited review for Journal of Physics G, 33pp; v2: references added and improved discussion of operator basis in section 2.

    Rydberg excitation of a single trapped ion

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    We demonstrate excitation of a single trapped cold 40^{40}Ca+^+ ion to Rydberg levels by laser radiation in the vacuum-ultraviolet at 122 nm wavelength. Observed resonances are identified as 3d2^2D3/2_{3/2} to 51 F, 52 F and 3d2^2D5/2_{5/2} to 64F. We model the lineshape and our results imply a large state-dependent coupling to the trapping potential. Rydberg ions are of great interest for future applications in quantum computing and simulation, in which large dipolar interactions are combined with the superb experimental control offered by Paul traps.Comment: 4 pages, 3 figure

    The Interest Sensitivity of Commercial Bank Equity Returns: New Evidence

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    Daniel T. Walz is an Associate Professor of Business Administration at Trinity University, San Antonio. Roger W. Spencer is Professor of Economics at Trinity University. San Antonio

    The Effects of Initial Dividend Announcements on Security Returns- Further Evidence

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    Daniel Walz is an Assistant Professor of Business Administration at Trinity University. Kalyan K. Roy is an Assistant Professor of Business Administration at the University of Calcutta

    Precious Metals And Retirement Portfolio Survival Rates

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    Recent gains in the value of gold bullion in the presence of declines in the stock and corporate bond markets suggest that retired investors may benefit from holdings of precious metals.  Because of the comparative liquidity and economy of holding mutual fund shares, we examine the effect of an optimal allocation of precious metals funds shares on portfolio survival rates through payout periods of 15, 20, 25, 30, and 35 years using returns data from September 1988 through December 2008.  Since most of the higher withdrawal rates that are supported by precious metals funds are ill-advised, adding precious metals fund shares to a conventional stocks and bonds portfolio does not appear to benefit most retired investors.  The findings do support greater allocations to bonds rather than stocks

    Laser cooling of new atomic and molecular species with ultrafast pulses

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    We propose a new laser cooling method for atomic species whose level structure makes traditional laser cooling difficult. For instance, laser cooling of hydrogen requires single-frequency vacuum-ultraviolet light, while multielectron atoms need single-frequency light at many widely separated frequencies. These restrictions can be eased by laser cooling on two-photon transitions with ultrafast pulse trains. Laser cooling of hydrogen, antihydrogen, and many other species appears feasible, and extension of the technique to molecules may be possible.Comment: revision of quant-ph/0306099, submitted to PR

    Continuous Lyman-alpha generation by four-wave mixing in mercury for laser-cooling of antihydrogen

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    Cooling antihydrogen atoms is important for future experiments both to test the fundamental CPT symmetry by high-resolution laser spectroscopy and also to measure the gravitational acceleration of antimatter. Laser-cooling of antihydrogen can be done on the strong 1S-2P transition at the wavelength of Lyman-alpha (121.6nm). A continuous-wave laser at the Lyman-alpha wavelength based on solid-state fundamental lasers is described. By using a two-photon and a near one photon resonance a scan across the whole phasematching curve of the four-wave mixing process is possible. Furthermore the influence of the beam profile of one fundamental beam on the four-wave mixing process is studied.Comment: 4 pages, 4 figure
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