22 research outputs found
Low-lying dipole response in the Relativistic Quasiparticle Time Blocking Approximation and its influence on neutron capture cross sections
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 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
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
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 effective-range parameters of some realistic nucleon-nucleon potentials
We consider the - and -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 in the models may be of significance.Comment: 16 pages, REVTEX, McM/Th-93-0
Predicting the ‘Global Financial Crisis’: post-Keynesian macroeconomics
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