3,185 research outputs found

    Antiproton-proton partial-wave analysis below 925 MeV/c

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    A partial-wave analysis of all antiproton-proton scattering data below 925 MeV/c antiproton laboratory momentum is presented. The method used is adapted from the Nijmegen phase-shift analyses of pp and np scattering data. The Nijmegen 1993 antiproton-proton database, consisting of 3646 antiproton-proton scattering data, is presented and discussed. The best fit to this database results in chi^2_min/Ndata = 1.043. The pseudovector coupling constant of the charged pion to nucleons is determined to be (f_c)^2 = 0.0732(11) at the pion pole, where the error is statistical.Comment: Report THEF-NYM 93.02 42 pages REVTeX, 7 separate postscript figures appended. Accepted for publication in Phys. Rev.

    Deuteron Dipole Polarizabilities and Sum Rules

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    The scalar, vector, and tensor components of the (generalized) deuteron electric polarizability are calculated, as well as their logarithmic modifications. Several of these quantities arise in the treatment of the nuclear corrections to the deuterium Lamb shift and the deuterium hyperfine structure. A variety of second-generation potential models are used and a (subjective) error is assigned to the calculations. The zero-range approximation is used to analyze a subset of the results, and a simple relativistic version of this approximation is developed.Comment: 14 pages, LaTex - submitted to Physical Review

    The nucleon-sigma coupling constant in QCD Sum Rules

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    The external-field QCD Sum Rules method is used to evaluate the coupling constant of the light isoscalar-scalar meson (``σ\sigma'' or \epsilon) to the nucleon. The contributions that come from the excited nucleon states and the response of the continuum threshold to the external field are calculated. The obtained value of the coupling constant is compatible with the large value required in one-boson exchange potential models of the two-nucleon interaction.Comment: 11 pages, 4 figure

    Synonchium capense n. sp. from South Africa (Nematoda : Cyatholaimidae)

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    #Synonchium capense n. sp. provenant de dunes sableuses des côtes d'Afrique du Sud est décrit. Il diffère de l'espèce type, #S. obtusum Cobb, 1920, par la présence de trois dents de même taille à l'apex de chaque mandibule et par l'absence de ponctuations sur la cuticule. La nouvelle espèce est également comparée à #S. depressum Gerlach, 1954 et #S. pacificum Yeates, 1967, et une clé d'identification est proposée pour les quatre espèces connues. La morphologie des papilles labiales et céphaliques et l'anatomie de la gonade mâle chez les espèces du genre sont discutées. Un important organe glandulaire associé au système reproducteur femelle est décrit chez #S. capense$ n. sp. (Résumé d'auteur

    Partial Wave Analyses of the pp data alone and of the np data alone

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    We present results of the Nijmegen partial-wave analyses of all NN scattering data below Tlab = 500 MeV. We have been able to extract for the first time the important np phase shifts for both I = 0 and I = 1 from the np scattering data alone. This allows us to study the charge independence breaking between the pp and np I = 1 phases. In our analyses we obtain for the pp data chi^2_{min}/Ndf = 1.13 and for the np data chi^2_{min}/Ndf = 1.12.Comment: Report THEF-NYM 94.04, 4 pages LaTeX, one PostScript figure appended. Contribution to the 14th Few-Body Conference, May 26 - 31, Williamsburg, V

    Report on uncertainty methods

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    The issue of uncertainty is critical for climate change science and policy. A great deal of research analysis has gone into identifying the scope and character of uncertainty in climate change itself, in how analysts and assessment teams can and should communicate that uncertainty to policy- and decision-makers, and how policy- and decision-makers can then incorporate nowledge about the sources and magnitude of uncertainty in their choices. The primary purpose of this deliverable is to summarize that literature, and to synthesize it in a manner that is useful for the Mediation project, namely in improving the practice of assessing adaptaion needs and options, and in building a useful decision-support platform or system. The report starts with a user-driven focus, summarizing the literatures on both descriptive and normative models of decision-making under uncertainty, in order to identify the most effective and esential information inputs for each of these models. The report then summarizes some of the main guidance documents on communicating uncertanty, prepared for or in use by the Intergovernmental Panel on Climate Change, the United States government, and the Dutch government. Fially, the report synthesizes these previous studies for use in the Mediation project and its users by focusing on three essential characteristics of uncertainty communication: parsimony, personalization, and practicality. It identifies specific strategies for using these three criteria to ensure that assessments for climate adaptation are salient, credible, and legitimate, and thus ultimately construtive inputs into policy- and decision-making
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