459 research outputs found

    Production of exotic isotopes in complete fusion reactions with radioactive beams

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    The isotopic dependence of the complete fusion (capture) cross section is analyzed in the reactions 130,132,134,136,138,140,142,144,146,148,150^{130,132,134,136,138,140,142,144,146,148,150}Xe+48^{48}Ca with stable and radioactive beams. It is shown for the first time that the very neutron-rich nuclei 186−191^{186-191}W can be reached with relatively large cross sections by complete fusion reactions with radioactive ion beams at incident energies near the Coulomb barrier. A comparison between the complete fusion and fragmentation reactions for the production of neutron-rich W and neutron-deficient Rn isotopes is performed.Comment: 13 pages, 6 figures, accepted in PR

    Pauli-Villars Regularization in nonperturbative Hamiltonian approach on the Light Front

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    The advantage of Pauli-Villars regularization in quantum field theory quantized on the light front is explained. Simple examples of scalar λφ4\lambda\varphi^4 field theory and Yukawa-type model are used. We give also an example of nonperturbative calculation in the theory with Pauli-Villars fields, using for that a model of anharmonic oscillator modified by inclusion of ghost variables playing the role similar to Pauli-Villars fields.Comment: LaTeX, 10 pages, 2 figures. Article will be published in AIP Conference Proceedings, the final publication will be available at http://scitation.aip.org/content/aip/proceeding/aipc

    An ab initio theory of double odd-even mass differences in nuclei

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    Two aspects of the problem of evaluating double odd-even mass differences D_2 in semi-magic nuclei are studied related to existence of two components with different properties, a superfluid nuclear subsystem and a non-superfluid one. For the superfluid subsystem, the difference D_2 is approximately equal to 2\Delta, the gap \Delta being the solution of the gap equation. For the non-superfluid subsystem, D_2 is found by solving the equation for two-particle Green function for normal systems. Both equations under consideration contain the same effective pairing interaction. For the latter, the semi-microscopic model is used in which the main term calculated from the first principles is supplemented with a small phenomenological addendum containing one phenomenological parameter supposed to be universal for all medium and heavy atomic nuclei.Comment: 7 pages, 10 figures, Report at Nuclear Structure and Related Topics, Dubna, Russia, July 2 - July 7, 201

    The first quadrupole excitations in spherical nuclei and nuclear pairing

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    Excitation energies and transition probabilities of the first 2+ excitations in even lead, tin and nickel isotopes are calculated within the self-consistent Theory of Finite Fermi Systems based on the Energy Density Functional by Fayans et al. A reasonable agreement with available experimental data is obtained. The effect of the density dependence of the effective pairing interaction is analyzed in detail by comparing results obtained with volume and surface pairing. The effect is found to be noticeable, especially for the 2+ energies which are systematically higher at 200-300 keV for the volume paring as compared with the surface pairing case, the latter being in a better agreement with the data.Comment: Presented at International Conference on Nuclear Structure and Related Topics, Dubna, July 2 - 7, 201

    Description of a new species of Chrysina Kirby, 1828 (Coleoptera: Scarabaeidae: Rutelinae) from resplendens group, based on morphological characters and mtDNA COX I molecular marker

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    A new species of the genus Chrysina Kirby, 1828 is decribed from Panama. Chrysina kalinini sp.n. is related to Chrysina resplendens (Boucard, 1875) in habitus, male genitalia morphology and mtDNA COX I molecular marker). The two closely related species differ in the shape of pronotum, mesosternal process and male genitalia. mtDNA COI molecular marker analysis gives a reliable distance for the compared species
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