22 research outputs found

    Low-lying dipole response in the Relativistic Quasiparticle Time Blocking Approximation and its influence on neutron capture cross sections

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    We have computed dipole strength distributions for nickel and tin isotopes within the Relativistic Quasiparticle Time Blocking approximation (RQTBA). These calculations provide a good description of data, including the neutron-rich tin isotopes 130,132^{130,132}Sn. The resulting dipole strengths have been implemented in Hauser-Feshbach calculations of astrophysical neutron capture rates relevant for r-process nucleosynthesis studies. The RQTBA calculations show the presence of enhanced dipole strength at energies around the neutron threshold for neutron rich nuclei. The computed neutron capture rates are sensitive to the fine structure of the low lying dipole strength, which emphasizes the importance of a reliable knowledge of this excitation mode.Comment: 15 pages, 4 figures, Accepted in Nucl. Phys.

    Hadronic Parity Violation and Inelastic Electron-Deuteron Scattering

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    We compute contributions to the parity-violating (PV) inelastic electron-deuteron scattering asymmetry arising from hadronic PV. While hadronic PV effects can be relatively important in PV threshold electro- disintegration, we find that they are highly suppressed at quasielastic kinematics. The interpretation of the PV quasielastic asymmetry is, thus, largely unaffected by hadronic PV.Comment: 27 pages, 13 figures, uses REVTeX and BibTe

    Causality bounds for neutron-proton scattering

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    We consider the constraints of causality and unitarity for the low-energy interactions of protons and neutrons. We derive a general theorem that non-vanishing partial-wave mixing cannot be reproduced with zero-range interactions without violating causality or unitarity. We define and calculate interaction length scales which we call the causal range and the Cauchy-Schwarz range for all spin channels up to J = 3. For some channels we find that these length scales are as large as 5 fm. We investigate the origin of these large lengths and discuss their significance for the choice of momentum cutoff scales in effective field theory and universality in many-body Fermi systems.Comment: 36 pages, 10 figures, 7 tables, version to appear in Eur. Phys. J.

    The 3S13D1^3S_1-^3D_1 effective-range parameters of some realistic nucleon-nucleon potentials

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    We consider the PP- and QQ-shape parameters in the eigenphase and `bar' phase shift representations for the two Reid potentials and the more recent Moscow potential. The values of these parameters were obtained from integrals of the zero-energy wave function in a similar manner to that for the effective range. Such expressions for the shape parameters yield more reliable numerical values of the shape parameter than those obtained by least-mean-square or polynomial fits. We show that the eigenphase representation is more meaningful than the `bar' phase shift representation and that the variation in the values of PαP_\alpha in the models may be of significance.Comment: 16 pages, REVTEX, McM/Th-93-0

    Predicting the ‘Global Financial Crisis’: post-Keynesian macroeconomics

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    The 'Global Financial Crisis' is widely acknowledged to be a tail event for neoclassical economics (Stevens, 2008), but it was an expected outcome for a range of non-neoclassical economists from the Austrian and post-Keynesian schools. This article provides a survey of the post-Keynesian approach for readers who are not familiar with this literature. It will briefly cover the history of how post-Keynesian economics came to diverge so much from the neoclassical mainstream, and focus on post-Keynesian macroeconomics today and its alternative indicators of macroeconomic turbulence
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