132 research outputs found

    Fine Structure Discussion of Parity-Nonconserving Neutron Scattering at Epithermal Energies

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    The large magnitude and the sign correlation effect in the parity non-conserving resonant scattering of epithermal neutrons from 232^{232}Th is discussed in terms of a non-collective 2p1h2p-1h local doorway model. General conclusions are drawn as to the probability of finding large parity violation effects in other regions of the periodic table.Comment: 6 pages, Tex. CTP# 2296, to appear in Z. Phys.

    Rings and bars: unmasking secular evolution of galaxies

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    Secular evolution gradually shapes galaxies by internal processes, in contrast to early cosmological evolution which is more rapid. An important driver of secular evolution is the flow of gas from the disk into the central regions, often under the influence of a bar. In this paper, we review several new observational results on bars and nuclear rings in galaxies. They show that these components are intimately linked to each other, and to the properties of their host galaxy. We briefly discuss how upcoming observations, e.g., imaging from the Spitzer Survey of Stellar Structure in Galaxies (S4G), will lead to significant further advances in this area of research.Comment: Invited review at "Galaxies and their Masks", celebrating Ken Freeman's 70-th birthday, Sossusvlei, Namibia, April 2010. To be published by Springer, New York, editors D.L. Block, K.C. Freeman, & I. Puerari; minor change

    Study of the decay mode D^0 -> K-K-K+pi+

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    Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode D0KKK+π+D^0 \to K^-K^-K^+\pi^+. From a sample of 143±19143 \pm 19 fully reconstructed D0KKK+π+D^0 \to K^-K^-K^+\pi^+ events, we measure Γ(D0KKK+π+)/Γ(D0Kππ+π+)=0.00257±0.00034(stat.)±0.00024(syst.)\Gamma(D^0 \to K^-K^-K^+\pi^+)/\Gamma(D^0 \to K^-\pi^-\pi^+\pi^+) = 0.00257 \pm 0.00034(stat.) \pm 0.00024(syst.). A coherent amplitude analysis has been performed to determine the resonant substructure of this decay mode. This analysis reveals a dominant contribution from ϕ\phi and Kˉ0(890)\bar K^{*0}(890) states.Comment: 15 pages, 4 figures, to be submitted to Physics Letters

    Search for Colour Singlet and Colour Reconnection Effects in Hadronic Z Decays at LEP

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    A search is performed in symmetric 3-jet hadronic Z decay events for evidence of colour singlet production or colour reconnection effects. Asymmetries in the angular separation of particles are found to be sensitive indicators of such effects. Upper limits on the level of colour singlet production and colour reconnection effects are established for a variety of models
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