328 research outputs found

    Dynamics of the Pionium with the Density Matrix Formalism

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    The evolution of pionium, the π+π\pi^+ \pi^- hydrogen-like atom, while passing through matter is solved within the density matrix formalism in the first Born approximation. We compare the influence on the pionium break-up probability between the standard probabilistic calculations and the more precise picture of the density matrix formalism accounting for interference effects. We focus our general result in the particular conditions of the DIRAC experiment at CERN.Comment: 14 pages, 2 figures, submitted to J. Phys. B: At. Mol. Phy

    Hadronic Atoms and Effective Interactions

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    We examine the problem of hadronic atom energy shifts using the technique of effective interactions and demonstrate equivalence with the conventional quantum mechanical approach.Comment: 22 page latex file with 2 figure

    Direct calculation of the probability of pionium ionization in the target

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    We performed the first direct calculation of the probability of pionium (pi+pi- atom) ionization in the target. The dependence of the probability of pionium ionization in the target as a function of the pionium lifetime is established. These calculations are of interest of the DIRAC experiment at CERN, which aims to measure the pionium lifetime with high precision.Comment: 11 pages, 4 figures; submitted to "Physics of Atomic Nuclei" ("Yadernaya Fizika"

    A Complete Version of the Glauber Theory for Elementary Atom - Target Atom Scattering and Its Approximations

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    A general formalism of the Glauber theory for elementary atom (EA) - target atom (TA) scattering is developed. A second-order approximation of its complete version is considered in the framework of the optical-model perturbative approach. A `potential' approximation of a second-order optical model is formulated neglecting the excitation effects of the TA. Its accuracy is evaluated within the second-order approximation for the complete version of the Glauber EA-TA scattering theory.Comment: PDFLaTeX, 10 pages, no figures; an updated versio

    Historical approaches, effective solutions and promising developments of the national school of management for the mobilization of ecosystem potential

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    The article presents a retrospective analysis of the processes for formulation and solving problems of complex development: theory and practice of management based on traditional and innovative approaches of the Russian scientific school. The evolution of the main trends is analyzed in the formation and development of key concepts in the field of construction and application by infrastructures of socioeconomic organizations. The following basic laws, fundamental principles, effective mechanisms and promising models of the organization of coordinated interaction of subjects (in the sphere of economic activity and within the framework of regionally and technologically determined production and commercial formations) are distinguished and compared. The prospects of improving the work of territorial and sectoral management mechanisms are considered from the standpoint of ensuring harmonious interaction, constructive innovations and sustainable development. The priorities of the formation and mobilization of the potential of ecosystems are determined as the most promising constructions of modern sectoral and regional complexes ensuring the harmonious use of socio-economic resources of modern society. The content of the perspective modernization is presented of the most significant provisions in the theory and practice of purposeful influence, revealing the priorities and trends of improving the formulation, as well as the application of the fundamental concepts of the national scientific school of management

    Coronal Shock Waves, EUV waves, and their Relation to CMEs. II. Modeling MHD Shock Wave Propagation Along the Solar Surface, Using Nonlinear Geometrical Acoustics

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    We model the propagation of a coronal shock wave, using nonlinear geometrical acoustics. The method is based on the Wentzel-Kramers-Brillouin (WKB) approach and takes into account the main properties of nonlinear waves: i) dependence of the wave front velocity on the wave amplitude, ii) nonlinear dissipation of the wave energy, and iii) progressive increase in the duration of solitary shock waves. We address the method in detail and present results of the modeling of the propagation of shock-associated extreme-ultraviolet (EUV) waves as well as Moreton waves along the solar surface in the simplest solar corona model. The calculations reveal deceleration and lengthening of the waves. In contrast, waves considered in the linear approximation keep their length unchanged and slightly accelerate.Comment: 15 pages, 7 figures, accepted for publication in Solar Physic
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