3,634 research outputs found

    D_{sJ}(2860) as the first radial excitation of the D_{s0}^*(2317)

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    A coupled-channel model previously employed to describe the narrow Ds0∗D_{s0}^*(2317) and broad D0∗D_0^*(2400) charmed scalar mesons is generalized so as to include all ground-state pseudoscalar-pseudoscalar and vector-vector two-meson channels. All parameters are chosen fixed at published values, except for the overall coupling constant, which is fine-tuned to reproduce the Ds0∗D_{s0}^*(2317) mass. Thus, the radial excitations Ds0∗D_{s0}^*(2850) and D0∗D_0^*(2740) are predicted, both with a width of about 50 MeV. The former state appears to correspond to the new DsJD_{sJ}(2860) resonance decaying to DKDK announced by BABAR in the course of this work. Also the D0∗D_0^*(2400) resonance is roughly reproduced, though perhaps with a somewhat too low central resonance peak.Comment: Plain LaTeX, 4 pages, 2 Postscript figures; v2: REVTeX, 4 pages, introduction expanded, "Note added in proof" and references added, figures with more detail and improved quality, version accepted for publication in Physical Review Letter

    Multichannel calculation of the very narrow Ds0∗(2317)D_{s0}^*(2317) and the very broad D0∗(2300−2400)D_0^*(2300-2400)

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    The narrow Ds0∗D_{s0}^{\ast}(2317) and broad D0∗D_0^{\ast}(2300-2400) charmed scalar mesons and their radial excitations are described in a coupled-channel quark model that also reproduces the properties of the light scalar nonet. All two-meson channels containing ground-state pseudoscalars and vectors are included. The parameters are chosen fixed at published values, except for the overall coupling constant λ\lambda, which is fine-tuned to reproduce the Ds0∗D_{s0}^{\ast}(2317) mass, and a damping constant α\alpha for subthreshold contributions. Variations of λ\lambda and D0∗D_0^{\ast}(2300-2400) pole postions are studied for different α\alpha values. Calculated cross sections for SS-wave DKDK and DπD\pi scattering, as well as resonance pole positions, are given for the value of α\alpha that fits the light scalars. The thus predicted radially excited state Ds0∗′{D_{s0}^*}'(2850), with a width of about 50 MeV, seems to have been observed already.Comment: 3 pages, EPJ LaTeX, 2 Postscript figures, 1 table; parallel talk at the IVth International Conference on Quarks and Nuclear Physics (QNP06), Madrid, 5-10 June 200

    The Use of Classical Mythology in Edmund Spenser\u27s Faerie Queene Book I and II

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    For the proper understanding of this thesis, it is necessary to state explicitly what it does not attempt to do. It is absolutely not an examination into the sources of Spenser\u27s classical mythology. That research work has already been done in two published studies; namely, The Sources of Spenser\u27s Classical Mythology by A. E. Sawtelle and a second work with the same title by A. S. Randall. The connection of Virgil and Spenser has been treated by M. G. Hughes in Virgil and Spenser

    A very broad X(4260) and the resonance parameters of the 3D vector charmonium state

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    We argue that the X(4260) enhancement contains a wealth of information on vector c-cbar spectroscopy. We discuss the shape of the X(4260) observed in the OZI-forbidden process "electron-positron into J/psi and a pair of charged pions", in particular at and near vector charmonium resonances as well as open-charm threshold enhancements. The resulting very broad X(4260) structure does not seem to classify itself as a vector charmonium resonance, but its detailed shape allows to identify new vector c-cbar states. Here, we estimate the resonance parameters of the psi(3D) state.Comment: 4 pages, 5 figures; version 2: 2 figures replace

    The effects of age and ganglioside composition on the rate of motor nerve terminal regeneration following antibody-mediated injury in mice

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    Gangliosides are glycosphingolipids highly enriched in neural plasma membranes, where they mediate a diverse range of functions and can act as targets for auto-antibodies present in human immune-mediated neuropathy sera. The ensuing autoimmune injury results in axonal and motor nerve terminal (mNT) degeneration. Both aging and ganglioside-deficiency have been linked to impaired axonal regeneration. To assess the effects of age and ganglioside expression on mNT regeneration in an autoimmune injury paradigm, anti-ganglioside antibodies and complement were applied to young adult and aged mice wildtype (WT) mice, mice deficient in either b- and c-series (GD3sKO) or mice deficient in all complex gangliosides (GM2sKO). The extent of mNT injury and regeneration was assessed immediately or after 5 days, respectively. Depending on ganglioside expression and antibody-specificity, either a selective mNT injury or a combined injury of mNTs and neuromuscular glial cells was elicited. Immediately after induction of the injury, between 1.5% and 11.8% of neuromuscular junctions (NMJs) in the young adult groups exhibited healthy mNTs. Five days later, most NMJs, regardless of age and strain, had recovered their mNTs. No significant differences could be observed between young and aged WT and GM2sKO mice; aged GD3sKO showed a mildly impaired rate of mNT regeneration when compared with their younger counterparts. Comparable rates were observed between all strains in the young and the aged mice. In summary, the rate of mNT regeneration following anti-ganglioside antibody and complement-mediated injury does not differ majorly between young adult and aged mice irrespective of the expression of particular gangliosides
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