97,432 research outputs found

    Kaon Condensation in ``Nuclear Star" Matter

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    The critical density for kaon condensation in ``nuclear star" matter is computed up to two-loop order {\it in medium} (corresponding to next-to-next-to-leading order in chiral perturbation theory in free space) with a heavy-baryon effective chiral Lagrangian whose parameters are determined from KNKN scattering and kaonic atom data. To the order considered, the kaon self-energy has highly non-linear density dependence in dense matter. We find that the four-Fermi interaction terms in the chiral Lagrangian play an important role in triggering condensation, predicting for ``natural" values of the four-Fermi interactions a rather low critical density, ρc<4ρ0\rho_c < 4 \rho_0.Comment: 12 pages and 2 figures(LaTeX), SNUTP-94-28. The fig. 3 is replaced, with some changes in the text but the conclusion is not affected by these change

    Dilatons for Dense Hadronic Matter

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    The idea that the explicit breaking of scale invariance by the trace anomaly of QCD can be rephrased as a spontaneous breaking has been recently exploited to capture the low-energy strong interaction dynamics of dense (and also hot) matter in terms of two dilaton fields, the "soft" (chi_s) and the "hard" (chi_h) fields, in the frame work of the hidden local gauge symmetry. In the Freund-Nambu model, the spontaneous symmetry breaking of scale symmetry is induced by an explicitly breaking term, while the spontaneous symmetry breaking is possible in the flat potential model which is scale symmetric. We discuss the interplay of the soft and hard dilatons using the spontaneously broken scale symmetry schemes and uncover a novel structure of dense matter hitherto unexplored.Comment: 7 pages, Invited talks presented at 4th International Conference on Symmetres in Subatomic Physics, June 2-5, 2009, Taipei, Taiwa

    Next Edition of IHO S-57 (Edition 4): Much more than ENCs

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    The primary goal for the next edition of S-57 (Edition 4) is to support a greater variety of hydrographic-related digital data sources, products, and customers. This includes matrix and raster data, 3-D and time-varying data (x, y, z, and time), and new applications that go beyond the scope of traditional hydrography (e.g., high-density bathymetry, seafloor classification, marine GIS). It will also enable the use of web-based services for data discovery, browsing, query, analysis, and transfer. S-57 Edition 4.0 will not be an incremental revision of Edition 3.1. Edition 4 will be a new standard that includes both additional content and a new data exchange format. Due to the world-wide prominence of ISO standards, IHO S-57 will conform to the “ISO way” of standards development. However, alignment with the ISO 19100 series of geographic standards will require a re-structuring of S-57 Edition 4. More specifically, this requires a new framework, and a new (or revised) set of terms used to describe the components of S-57 Edition 4.0. The present intention is to release Edition 4.0 in late 2006. Edition 3.1 will continue to be valid for many years to come -- even after Edition 4.0 has been released. Since most ECDIS equipment use ENC data conforming to the ENC Product Specification contained in S-57 Edition 3.1, Hydrographic Offices should continue to produce Edition 3.1 ENC data in order to continue to improve world-wide ENC coverage. Current plans are to release a new ENC Product Specification approximately one year after publication of S-57 Edition 4.0

    Vector Mesons and Dence Skyrmion Matter

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    In our continuing effort to understand hadronic matter at high density, we have developed a unified field theoretic formalism for dense skyrmion matter using a single Lagrangian to describe simultaneously both matter and meson fluctuations and studied in-medium properties of hadrons. Dropping the quartic Skyrme term, we incorporate into our previous Lagrangian the vector mesons rho and omega in a form which is consistent with the symmetries of QCD. The results that we have obtained, reported here, expose a hitherto unsuspected puzzle associated with the role the omega meson plays at short distance. Since the omega meson couples to baryon density, it leads to a pseudo-gap scenario for the chiral symmetry phase transition, which is at variance with standard scenario of QCD at the phase transition. We find that in the presence of the omega mesons, the scale-anomaly dilaton field is prevented from developing a vanishing vacuum expectation value at the chiral restoration, as a consequence of which the in-medium pion decay constant does not vanish. This seems to indicate that the omega degree of freedom obstructs the vector manifestation which is considered to be a generic feature of effective field theories matched to QCD.Comment: 16 pages, 5 figures, references for Sec.5 adde

    Tensor structure from scalar Feynman matroids

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    We show how to interpret the scalar Feynman integrals which appear when reducing tensor integrals as scalar Feynman integrals coming from certain nice matroids.Comment: 12 pages, corrections suggested by referee
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