30,161 research outputs found

### Excited-State Density Distributions of Neutron-Rich Unstable Nuclei

We calculate densities of excited states in the quasiparticle random-phase
approximation (QRPA)with Skyrme interactions and volume pairing. We focus on
low-energy peaks/bumps in the strength functions of a range of Ca, Ni, and Sn
isotopes for J pi = 0+, 1-, and 2+. We define an "emitted-neutron number",
which we then use to distinguish localized states from scattering-like states.
The degree of delocalization either increases as the neutron-drip line is
approached or stays high between the stability line and the drip line. In the
2+ channel of Sn, however, the low-lying states, not even counting surface
vibrations, are still fairly well localized on average, even at the neutron
drip line.Comment: 4 pages, 4 figure

### Intrinsic-Density Functionals

The Hohenberg-Kohn theorem and Kohn-Sham procedure are extended to
functionals of the localized intrinsic density of a self-bound system such as a
nucleus. After defining the intrinsic-density functional, we modify the usual
Kohn-Sham procedure slightly to evaluate the mean-field approximation to the
functional, and carefully describe the construction of the leading corrections
for a system of fermions in one dimension with a spin-degeneracy equal to the
number of particles N. Despite the fact that the corrections are complicated
and nonlocal, we are able to construct a local Skyrme-like intrinsic-density
functional that, while different from the exact functional, shares with it a
minimum value equal to the exact ground-state energy at the exact ground-state
intrinsic density, to next-to-leading order in 1/N. We briefly discuss
implications for real Skyrme functionals.Comment: 15 page

### Impact of Uncertainties in Hadron Production on Air-Shower Predictions

At high energy, cosmic rays can only be studied by measuring the extensive
air showers they produce in the atmosphere of the Earth. Although the main
features of air showers can be understood within a simple model of successive
interactions, detailed simulations and a realistic description of particle
production are needed to calculate observables relevant to air shower
experiments. Currently hadronic interaction models are the main source of
uncertainty of such simulations. We will study the effect of using different
hadronic models available in CORSIKA and CONEX on extensive air shower
predictions.Comment: 12 pages, 6 figures, to appear in the proceedings of International
Conference on Interconnection between High Energy Physics and Astroparticle
Physics: From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 Sep 200

### Schiff Screening of Relativistic Nucleon Electric-Dipole Moments by Electrons

We show, at leading-order in the multipole expansion of the electron-nucleus
interaction, that nucleon electric-dipole moments are completely shielded by
electrons so that they contribute nothing to atomic electric-dipole moments,
even when relativity in the nucleus is taken into account. It is well known
that relativistic electron motion, by contrast, leads to dipole moments that
are not screened; we discuss the reasons for the difference.Comment: 4 pages, typeset by REVTeX, submitted to PR

### Large-Scale Calculations of the Double-Beta Decay of 76Ge, 130Te, 136Xe, and 150Nd in the Deformed Self-Consistent Skyrme Quasiparticle Random-Phase Approximation

We use the axially-deformed Skyrme Quasiparticle Random-Phase Approximation
(QRPA) together with the SkM* energy-density functional, both as originally
presented and with the time-odd part adjusted to reproduce the Gamow-Teller
resonance energy in 208Pb, to calculate the matrix elements governing the
neutrinoless double-beta decay of 76Ge, 130Te, 136Xe, and 150Nd. Our matrix
elements in 130Te and 136Xe are significantly smaller than those of previous
QRPA calculations, primarily because of the difference in pairing or
deformation between the initial and final nuclei. In 76Ge and 150Nd our results
are similar to those of less computationally intensive QRPA calculations. We
suspect the 76Ge result, however, because we are forced to use a spherical
ground-state, even though the HFB indicates a deformed minimum.Comment: 9 pages, 4 figure

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