52,634 research outputs found

    Systematics of q anti-q states in the (n,M^2) and (J,M^2) planes

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    In the mass region up to M < 2400 MeV we systematise mesons on the plots (n,M^2) and (J,M^2), thus setting their classification in terms of n^{2S+1}L_J q anti-q states. The trajectories on the (n,M^2)-plots are drawn for the following (IJ^{PC})-states: a_0(10^{++}), a_1(11^{++}), a_2(12^{++}), a_3(13^{++}), a_4(14^{++}), pi(10^{-+}), pi_2(12^{-+}), eta(00^{-+}), eta_2(02^{-+})$, rho(11^{--}), f_0(00^{++}), f_2(02^{++}). All trajectories are linear, with nearly the same slopes. At the (J,M^2)-plot we set out meson states for leading and daughter trajectories: for pi, rho, a_1, a_2 and P'.Comment: 6 pages, LaTeX, 16 EPS figures, epsfig.st

    New variables of separation for particular case of the Kowalevski top

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    We discuss the polynomial bi-Hamiltonian structures for the Kowalevski top in special case of zero square integral. An explicit procedure to find variables of separation and separation relations is considered in detail.Comment: 11 pages, LaTeX with Ams font

    Can Intelligent Environments be Trustworthy? Designing for trust in Scientific Communication: Concept of Habitable Interfaces (Position Paper)

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    In this paper we propose the concept of Habitable Interfaces. This concept builds on values-based trust. We hypothesise that representations and interactions built on scientific metaphors and concepts and organised based on the knowledge whithin particular scientific domain will enable values-based trust. Habitable interfaces may provide better information exchange within scientific communities

    Modelling generalized parton distributions to describe deeply virtual Compton scattering data

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    We present a new model for generalized parton distributions (GPDs), based on the aligned jet model, which successfully describes the deeply virtual Compton scattering (DVCS) data from H1, ZEUS, HERMES and CLAS. We also present an easily implementable and flexible algorithm for their construction. This new model is necessary since the most widely used models for GPDs, which are based on factorized double distributions, cannot, in their current form, describe the DVCS data when employed in a full QCD analysis. We demonstrate explicitly the reason for the shortcoming in the data description. We also highlight several non-perturbative input parameters which could be used to tune the GPDs, and the tt-dependence, to the DVCS data using a fitting procedure.Comment: 12 pages, 12 figures, revtex4, shortened version accepted for publication in PRD, figures improved and references adde

    Twist-three analysis of photon electroproduction with pion

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    We study twist-three effects in spin, charge, and azimuthal asymmetries in deeply virtual Compton scattering on a spin-zero target. Contributions which are power suppressed in 1/Q generate a new azimuthal angle dependence of the cross section which is not present in the leading twist results. On the other hand the leading twist terms are not modified by the twist three contributions. They may get corrected at twist four level. In the Wandzura-Wilczek approximation these new terms in the Fourier expansion with respect to the azimuthal angle are entirely determined by the twist-two skewed parton distributions. We also discuss more general issues like the general form of the angular dependence of the differential cross section, validity of factorization at twist-three level, and a relation of skewed parton distributions to spectral functions.Comment: 21 pages, LaTeX, 2 figures, text clarifications, an equation, a note and references adde

    Anisotropy of effective masses in CuInSe2

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    Anisotropy of the valence band is experimentally demonstrated in CuInSe2, a key component of the absorber layer in one of the leading thin-film solar cell technology. By changing the orientation of applied magnetic fields with respect to the crystal lattice, we measure considerable differences in the diamagnetic shifts and effective g-factors for the A and B free excitons. The resulting free exciton reduced masses are combined with a perturbation model for non-degenerate independent excitons and theoretical dielectric constants to provide the anisotropic effective hole masses, revealing anisotropies of 5.5 (4.2) for the A (B) valence bands

    Occurrence of the Macrocyclops distinctus (Richard) (Copepoda, cyclopoidida) in Rybinsk reservoir. [Translation of: Materialy po biologii i gidrologii Volzhskikh Vodokhranilishch. Moscow, Leningrad 1963, pp. 13-16]

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    This brief chapter describes the occurrence Macrocyclops distinctus in the littoral zone of the Rybinsk Reservoir. Sampling was undertaken in summer and autumn 1961. In order to facilitate distinction of M. distinctus and Macrocyclops fuscus the author presents drawings of the whole species and certain characteristic parts of the body, and also gives a description of M. distinctus, comparing it with M. fuscus

    Early diagnosis of microelement imbalance in newborns with respiratory distreess syndrome

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    Respiratory distress syndrome (RDS) gets the high rank in the neonatal mortality structure. It develops as the consequence after the surfactant deficiency state, but mostly the premature newborns obtain it. Microelement imbalance and deficiency provoke the disorders in vital processes as well as the postnatal life adaptation condition issues. The above mentioned statements give the background for investigation actuality of the premature newborn’s microelement supply particularly those, who have RDS. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3244

    Two electrons in an external oscillator potential: hidden algebraic structure

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    It is shown that the Coulomb correlation problem for a system of two electrons (two charged particles) in an external oscillator potential possesses a hidden sl2sl_2-algebraic structure being one of recently-discovered quasi-exactly-solvable problems. The origin of existing exact solutions to this problem, recently discovered by several authors, is explained. A degeneracy of energies in electron-electron and electron-positron correlation problems is found. It manifests the first appearence of hidden sl2sl_2-algebraic structure in atomic physics.Comment: 7 pages (plus one figure avaliable via direct request), LaTeX, Preprint IFUNAM FT 94-4

    Effect of Multiple Scattering on the Critical Electric Field for Runaway Electrons in the Atmosphere

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    A simple method for taking into account the multiple Coulomb scattering in construction of a separatrix (the line separating the regions of runaway and decelerating electrons in an electric field) is described. The desired line is obtained by solving a simple transcendental equation.Comment: 3 pages, 2 figure
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