4,675 research outputs found

    Physicists Thriving with Paperless Publishing

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    The Stanford Linear Accelerator Center (SLAC) and Deutsches Elektronen Synchrotron (DESY) libraries have been comprehensively cataloguing the High Energy Particle Physics (HEP) literature online since 1974. The core database, SPIRES-HEP, now indexes over 400,000 research articles, with almost 50% linked to fulltext electronic versions (this site now has over 15 000 hits per day). This database motivated the creation of the first site in the United States for the World Wide Web at SLAC. With this database and the invention of the Los Alamos E-print archives in 1991, the HEP community pioneered the trend to "paperless publishing" and the trend to paperless access; in other words, the "virtual library." We examine the impact this has had both on the way scientists research and on paper-based publishing. The standard of work archived at Los Alamos is very high. 70% of papers are eventually published in journals and another 20% are in conference proceedings. As a service to authors, the SPIRES-HEP collaboration has been ensuring that as much information as possible is included with each bibliographic entry for a paper. Such meta-data can include tables of the experimental data that researchers can easily use to perform their own analyses as well as detailed descriptions of the experiment, citation tracking, and links to full-text documents.Comment: 17 pages, Invited talk at the AAAS Meeting, February 2000 in Washington, D

    Isospin Symmetry Breaking within the HLS Model: A Full (ρ,ω,ϕ\rho, \omega, \phi) Mixing Scheme

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    We study the way isospin symmetry violation can be generated within the Hidden Local Symmetry (HLS) Model. We show that isospin symmetry breaking effects on pseudoscalar mesons naturally induces correspondingly effects within the physics of vector mesons, through kaon loops. In this way, one recovers all features traditionally expected from \rho-\omg mixing and one finds support for the Orsay phase modelling of the e^+e^- \ra \pi^+ \pi^- amplitude. We then examine an effective procedure which generates mixing in the whole ρ\rho, \omg, ϕ\phi sector of the HLS Model. The corresponding model allows us to account for all two body decays of light mesons accessible to the HLS model in modulus and phase, leaving aside the \rho \ra \pi \pi and K^* \ra K \pi modes only, which raise a specific problem. Comparison with experimental data is performed and covers modulus and phase information; this represents 26 physics quantities successfully described with very good fit quality within a constrained model which accounts for SU(3) breaking, nonet symmetry breaking in the pseudoscalar sector and, now, isospin symmetry breaking.Comment: 38 pages, version published in Eur. Phys. J.

    VMD, the WZW Lagrangian and ChPT: The Third Mixing Angle

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    We show that the Hidden Local Symmetry Model, supplemented with well-known procedures for breaking flavor SU(3) and nonet symmetry, provides all the information contained in the standard Chiral Perturbation Theory (ChPT) Lagrangian L(0)+L(1){\cal L}^{(0)}+{\cal L}^{(1)}. This allows to rely on radiative decays of light mesons (VPγVP\gamma and PγγP \gamma\gamma) in order to extract some numerical information of relevance to ChPT: a value for Λ1=0.20±0.04\Lambda_1=0.20 \pm 0.04, a quark mass ratio of 21.2±2.4\simeq 21.2 \pm 2.4, and a negligible departure from the Gell-Mann--Okubo mass formula. The mixing angles are θ8=20.40±0.96\theta_8=-20.40^\circ \pm 0.96^\circ and θ0=0.05±0.99\theta_0=-0.05^\circ \pm 0.99^\circ. We also give the values of all decay constants. It is shown that the common mixing pattern with one mixing angle θP\theta_P is actually quite appropriate and algebraically related to the η/η\eta/\eta' mixing pattern presently preferred by the ChPT community. For instance the traditional θP\theta_P is functionally related to the ChPT θ8\theta_8 and fulfills θPθ8/2\theta_P \simeq \theta_8/2. The vanishing of θ0\theta_0, supported by all data on radiative decays, gives a novel relation between mixing angles and the violation of nonet symmetry in the pseudoscalar sector. Finally, it is shown that the interplay of nonet symmetry breaking through U(3) \ra SU(3)×\times U(1) satisfies all requirements of the physics of radiative decays without any need for additional glueballs.Comment: 31 pages, 1 figur

    The Lee-Wick Standard Model

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    We construct a modification of the standard model which stabilizes the Higgs mass against quadratically divergent radiative corrections, using ideas originally discussed by Lee and Wick in the context of a finite theory of quantum electrodynamics. The Lagrangian includes new higher derivative operators. We show that the higher derivative terms can be eliminated by introducing a set of auxiliary fields; this allows for convenient computation and makes the physical interpretation more transparent. Although the theory is unitary, it does not satisfy the usual analyticity conditions.Comment: 20 pages, 4 figures. Improved discussion and reference added. Contour prescription clarifie

    New results in rho^0 meson physics

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    We compare the predictions of a range of existing models based on the Vector Meson Dominance hypothesis with data on e^+ e^- -> pi^+ pi^$ and e^+ e^- -> mu^+ mu^- cross-sections and the phase and near-threshold behavior of the timelike pion form factor, with the aim of determining which (if any) of these models is capable of providing an accurate representation of the full range of experimental data. We find that, of the models considered, only that proposed by Bando et al. is able to consistently account for all information, provided one allows its parameter "a" to vary from the usual value of 2 to 2.4. Our fit with this model gives a point-like coupling (gamma pi^+ \pi^-) of magnitude ~ -e/6, while the common formulation of VMD excludes such a term. The resulting values for the rho mass and pi^+ pi^- and e^+e^- partial widths as well as the branching ratio for the decay omega -> pi^+ pi^- obtained within the context of this model are consistent with previous results.Comment: 34 pages with 7 figures. Published version also available at http://link.springer.de/link/service/journals/10052/tocs/t8002002.ht
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