6,771 research outputs found

    ALCOHOLS AS COMPONENTS OF TRANSPORTATION FUELS

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    Alcohols have the potential to revolutionize energy fuel supply and use, particularly in transportation. This worldwide potential is based on (a) the variety of widely available raw materials from which alcohols can be made (coal, natural gas, petroleum, and biomass), (b) the improved and demon­ strated technology for alcohol manufacture and use, and (c) the favorable combustion characteristics of alcohols, namely clean burning with high octane performance

    SuperB: a linear high-luminosity B Factory

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    This paper is based on the outcome of the activity that has taken place during the recent workshop on "SuperB in Italy" held in Frascati on November 11-12, 2005. The workshop was opened by a theoretical introduction of Marco Ciuchini and was structured in two working groups. One focused on the machine and the other on the detector and experimental issues. The present status on CP is mainly based on the results achieved by BaBar and Belle. Estabilishment of the indirect CP violation in B sector in 2001 and of the direct CP violation in 2004 thanks to the success of PEP-II and KEKB e+e- asymmetric B Factories operating at the center of mass energy corresponding to the mass of the Y(4s). With the two B Factories taking data, the Unitarity Triangle is now beginning to be overconstrained by improving the measurements of the sides and now also of the angles alpha, and gamma. We are also in presence of the very intriguing results about the measurements of sin(2 beta) in the time dependent analysis of decay channels via penguin loops, where b --> s sbar s and b --> s dbar d. Tau physics, in particular LFV search, as well as charm and ISR physics are important parts of the scientific program of a SuperB Factory. The physics case together with possible scenarios for the high luminosity SuperB Factory based on the concepts of the Linear Collider and the related experimental issues are discussed.Comment: 22 pages, 22 figures, INFN Roadmap Repor

    First Observation of the Rare Decay Mode K-long -> e+ e-

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    In an experiment designed to search for and study very rare two-body decay modes of the K-long, we have observed four examples of the decay K-long -> e+ e-, where the expected background is 0.17+-0.10 events. This observation translates into a branching fraction of 8.7^{+5.7}_{-4.1} X 10^{-12}, consistent with recent theoretical predictions. This result represents by far the smallest branching fraction yet measured in particle physics.Comment: 9 pages, 3 figure

    Renormalization Group Approach to the Coulomb Pseudopotential for C_{60}

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    A numerical renormalization group technique recently developed by one of us is used to analyse the Coulomb pseudopotential (μ{\mu^*}) in C60{{\rm C}_{60}} for a variety of bare potentials. We find a large reduction in μ{\mu^*} due to intraball screening alone, leading to an interesting non-monotonic dependence of μ{\mu^*} on the bare interaction strength. We find that μ{\mu^*} is positive for physically reasonable bare parameters, but small enough to make the electron-phonon coupling a viable mechanism for superconductivity in alkali-doped fullerides. We end with some open problems.Comment: 12 pages, latex, 7 figures available from [email protected]

    Search for the Weak Decay of an H Dibaryon

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    We have searched for a neutral HH dibaryon decaying via HΛnH\to\Lambda n and HΣ0nH\to\Sigma^0 n. Our search has yielded two candidate events from which we set an upper limit on the HH production cross section. Normalizing to the inclusive Λ\Lambda production cross section, we find (dσH/dΩ)/(dσΛ/dΩ)<6.3×106(d\sigma_H/d\Omega) / (d\sigma_\Lambda/d\Omega) < 6.3\times 10^{-6} at 90% C.L., for an HH of mass \approx 2.15 GeV/c2c^2.Comment: 11 pages, 6 postscript figures, epsfig, aps, preprint, revte

    Pion photoproduction on the nucleon in the quark model

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    We present a detailed quark-model study of pion photoproduction within the effective Lagrangian approach. Cross sections and single-polarization observables are investigated for the four charge channels, γpπ+n\gamma p\to \pi^+ n, γnπp\gamma n\to \pi^- p, γpπ0p\gamma p\to \pi^0 p, and γnπ0n\gamma n\to \pi^0 n. Leaving the πNΔ\pi N\Delta coupling strength to be a free parameter, we obtain a reasonably consistent description of these four channels from threshold to the first resonance region. Within this effective Lagrangian approach, strongly constrainted by the quark model, we consider the issue of double-counting which may occur if additional {\it t}-channel contributions are included.Comment: Revtex, 35 pages, 16 eps figures; version to appear on PR

    Search for Millicharged Particles at SLAC

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    Particles with electric charge q < 10^(-3)e and masses in the range 1--100 MeV/c^2 are not excluded by present experiments. An experiment uniquely suited to the production and detection of such "millicharged" particles has been carried out at SLAC. This experiment is sensitive to the infrequent excitation and ionization of matter expected from the passage of such a particle. Analysis of the data rules out a region of mass and charge, establishing, for example, a 95%-confidence upper limit on electric charge of 4.1X10^(-5)e for millicharged particles of mass 1 MeV/c^2 and 5.8X10^(-4)e for mass 100 MeV/c^2.Comment: 4 pages, REVTeX, multicol, 3 figures. Minor typo corrected. Submitted to Physical Review Letter
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