7,665 research outputs found

    Spin-orbit and tensor mean-field effects on spin-orbit splitting including self-consistent core polarizations

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    A new strategy of fitting the coupling constants of the nuclear energy density functional is proposed, which shifts attention from ground-state bulk to single-particle properties. The latter are analyzed in terms of the bare single-particle energies and mass, shape, and spin core-polarization effects. Fit of the isoscalar spin-orbit and both isoscalar and isovector tensor coupling constants directly to the f5/2-f7/2 spin-orbit splittings in 40Ca, 56Ni, and 48Ca is proposed as a practical realization of this new programme. It is shown that this fit requires drastic changes in the isoscalar spin-orbit strength and the tensor coupling constants as compared to the commonly accepted values but it considerably and systematically improves basic single-particle properties including spin-orbit splittings and magic-gap energies. Impact of these changes on nuclear binding energies is also discussed.Comment: 15 pages, 7 figures, submitted to Physical Review

    Finite size scaling analysis of intermittency moments in the two dimensional Ising model

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    Finite size scaling is shown to work very well for the block variables used in intermittency studies on a 2-d Ising lattice. The intermittency exponents so derived exhibit the expected relations to the magnetic critical exponent of the model. Email contact: [email protected]: Saclay-T93/063 Email: [email protected]

    An absorption spectrum amplifier for determining gas composition

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    Compositions of gas samples are frequently studied by laser absorption spectroscopy. Sensitivity is improved by two orders of magnitude when absorption cell is placed inside an organic-dye laser cavity

    Isgur-Wise Functions from the Mit Bag Model

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    The Isgur-Wise functions for the ground state to ground state semileptonic decays involving bcb \rightarrow c transitions are calculated from the (modified) MIT bag model. It is checked that the results for the decays BDlν\overline{B} \rightarrow D l \overline\nu and BDlν\overline{B} \rightarrow D^* l \overline\nu agree well with experiment. Predictions for the decays ΛbΛclν\Lambda_b \rightarrow \Lambda_c l \overline\nu, BsDslν\overline{B}_s \rightarrow D_s l \overline\nu and BsDslν\overline{B}_s \rightarrow D^*_s l \overline\nu are given and discussed.Comment: 12 pages (3 figures available upon request), LaTeX, TPJU - 9/9

    Global nuclear structure effects of tensor interaction

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    A direct fit of the isoscalar spin-orbit (SO) and both isoscalar and isovector tensor coupling constants to the f5/2-f7/2 SO splittings in 40Ca, 56Ni, and 48Ca nuclei requires a drastic reduction of the isoscalar SO strength and strong attractive tensor coupling constants. The aim of this work is to address further consequences of these strong attractive tensor and weak SO fields on binding energies, nuclear deformability, and high-spin states. In particular, we show that contribution to the nuclear binding energy due to the tensor field shows generic magic structure with tensorial magic numbers at N(Z)=14, 32, 56, or 90 corresponding to the maximum spin-asymmetries in 1d5/2, 1f7/2-2p3/2, 1g9/2-2d5/2 and 1h11/2-2f7/2 single-particle configurations and that these numbers are smeared out by pairing correlations and deformation effects. We also examine the consequences of strong attractive tensor fields and weak SO interaction on nuclear stability at the drip lines, in particular close to the tensorial doubly magic nuclei and discuss the possibility of an entirely new tensor-force driven deformation effect.Comment: replaced with published versio

    The anomalous threshold, confinement, and an essential singularity in the heavy-light form factor

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    The analytic behavior of the heavy-light meson form factor is investigated using several relativistic examples including unconfined, weakly confined, and strongly confined mesons. It is observed that confinement erases the anomalous threshold singularity and also induces an essential singularity at the normal annihilation threshold. In the weak confinement limit, the "would be" anomalous threshold contribution is identical to that of the real singularity on its space-like side.Comment: Latex 2.09 with epsf.sty. 24 pages of text and 8 postscript figures. Postscript version of complete paper will also be available soon at http://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-983 or at ftp://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-98

    Transmission Loss and Absorption of Corrugated Core Sandwich Panels With Embedded Resonators

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    The effect of embedded resonators on the diffuse field sound transmission loss and absorption of composite corrugated core sandwich panels has been evaluated experimentally. Two 1.219 m 2.438 m panels with embedded resonator arrangements targeting frequencies near 100 Hz were evaluated using non-standard processing of ASTM E90-09 acoustic transmission loss and ASTM C423-09a room absorption test measurements. Each panel is comprised of two composite face sheets sandwiching a corrugated core with a trapezoidal cross section. When inlet openings are introduced in one face sheet, the chambers within the core can be used as embedded acoustic resonators. Changes to the inlet and chamber partition locations allow this type of structure to be tuned for targeted spectrum passive noise control. Because the core chambers are aligned with the plane of the panel, the resonators can be tuned for low frequencies without compromising the sandwich panel construction, which is typically sized to meet static load requirements. Absorption and transmission loss performance improvements attributed to opening the inlets were apparent for some configurations and inconclusive for others
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