2,554 research outputs found

    Composite Skyrme Model with Vector Mesons

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    We study the composite Skyrme model, proposed by Cheung and G\"{u}rsey, introducing vector mesons in a chiral Lagrangian. We calculate the static properties of baryons and compare with results obtained from models without vector mesons.Comment: LaTeX, 9 pages, 3 figures, to be published in Phys. Rev.

    Stratigraphy of the Woodbine and Eagle Ford, Waco Area, Texas

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    In the last twenty years, very little detailed stratigraphy of this area has been published. Meanwhile there have been significant advances in this field: the aims of modern stratigraphic research have been somewhat clarified; much new information pertinent to the stratigraphy of this area has been accumulated from the study of other areas; and a considerable amount of detailed information on the surface and subsurface geology of this area has come to light as a result of detailed outcrop work, extensive drilling of oil tests and water wells, and new techniques of bore-hole logging. The scope of this work is mainly the study of beds located near the Lower-Upper Cretaceous boundary, from the Lower Washita to the base of the Austin chalk. This includes very detailed investigations of the Upper Washita beds and the Woodbine and Eagle Ford groups. The lithologic division and the fossil zonation of these strata are outlined, isopach and boundary maps of the various units presented, and the outcrop is tied into the subsurface. It is hoped that these results throw light on the division, definition, zonation, and stratigraphic behavior of both the Woodbine and the Eagle Ford in this area

    Recoil corrections in the hydrogen isoelectronic sequence

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    A version of the Bethe-Salpeter equation appropriate for calculating recoil corrections in highly charged hydrogenlike ions is presented. The nucleus is treated as a scalar particle of charge Z, and the electron treated relativistically. The known recoil corrections of order m2/M(Zα)4m^2/M(Z\alpha)^4 are derived in both this formalism and in NRQED

    The Single Photon Annihilation Contributions to the Positronium Hyperfine Splitting to Order meα6m_e\alpha^6

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    The single photon annihilation contributions for the positronium ground state hyperfine splitting are calculated analytically to order meα6m_e\alpha^6 using NRQED. Based on intuitive physical arguments the same result can also be determined by a trivial calculation using results from existing literature. Our result completes the hyperfine splitting calculation to order meα6m_e\alpha^6. We compare the theoretical prediction with the most recent experimental measurement.Comment: 8 pages, latex, two eps figures include

    University of Texas bulletin

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    Report published in a scientific bulletin, describing the geology and mineral resources that reside in McLennan county

    Some Ohio Heteroptera Records

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    Author Institution: Department of Anatomy, University of Illinois, Chicag

    alpha^2 corrections to parapositronium decay: a detailed description

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    We present details of our recent calculation of alpha^2 corrections to the parapositronium decay into two photons. These corrections are rather small and our final result for the parapositronium lifetime agrees well with the most recent measurement. Implications for orthopositronium decays are briefly discussed.Comment: 18 pages, late

    The "recoil" correction of order mα6m \alpha^6 to hyperfine splitting of positronium ground state

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    The "recoil" correction of order mα6m \alpha^6 to the hyperfine splitting of positronium ground state was found. The formalism employed is based on the noncovariant perturbation theory in QED. Equation for two-particle component of full (many-body) wave function is used, in which effective Hamiltonian depends on the energy of a system. The effective Hamiltonian is not restricted to the nonrelativistic region, so there is no need in any regularization. To evaluate integrals over loop momenta, they are divided into "hard" and "soft" parts, coming from large and small momenta respectively. Soft contributions were found analytically, and hard ones are evaluated by numerical integration. Some soft terms due to the retardation cancel each other. To calculate the "hard" contributions, a great number of noncovariant graphs is replaced by only a few covariant ones. The hard contribution was found in two ways. The first way is to evaluate contributions of separate graphs, using the Coulomb gauge. The second one is to calculate full hard contribution as a whole using the Feynman gauge. The final result for the "recoil" correction is 0.381(6) m\al^6 and agrees with those of previous papers. Diagram-to-diagram comparison with the revised results of Adkins&Sapirstein was done. All the results agree, so the "recoil" correction is now firmly established. This means a considerable disagreement with the experimental data.Comment: 28 pages, latex including latex figure
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