skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Comparison between the Gamow shell model and the cluster-orbital shell model for weakly bound systems

Abstract

We study contributions of poles and continua of the single-particle states to the wave function obtained by the cluster-orbital shell model (COSM). The COSM wave function is described in terms of a linear combination of nonorthogonal Gaussian basis sets. We study oxygen and helium isotopes as examples of normal and weakly bound nuclei. In the investigation of the contribution of the single-particle states, we expand the COSM wave function by using an extended completeness relation, which is constructed by the solution of the single-particle Hamiltonian. We use the complex scaling method to obtain the bound, resonant, and continuum states of the Hamiltonian and construct the extended completeness relation. The results are compared with those obtained by the Gamow shell model calculation.

Authors:
; ;  [1];  [2];  [3]
  1. Information Processing Center, Kitami Institute of Technology, Kitami 090-8507 (Japan)
  2. (Japan)
  3. (RIKEN), Wako, 351-0198 (Japan)
Publication Date:
OSTI Identifier:
20995129
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034316; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CLUSTER MODEL; COMPARATIVE EVALUATIONS; HAMILTONIANS; HELIUM ISOTOPES; MASS NUMBER; NUCLEI; OXYGEN ISOTOPES; PARTICLES; SHELL MODELS; WAVE FUNCTIONS

Citation Formats

Masui, H., Kato, K., Ikeda, K., Department of Physics, Faculty of Science, Hokkaido University, Sapporo, 060-0810, and Institute of Physical and Chemical Research. Comparison between the Gamow shell model and the cluster-orbital shell model for weakly bound systems. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.034316.
Masui, H., Kato, K., Ikeda, K., Department of Physics, Faculty of Science, Hokkaido University, Sapporo, 060-0810, & Institute of Physical and Chemical Research. Comparison between the Gamow shell model and the cluster-orbital shell model for weakly bound systems. United States. doi:10.1103/PHYSREVC.75.034316.
Masui, H., Kato, K., Ikeda, K., Department of Physics, Faculty of Science, Hokkaido University, Sapporo, 060-0810, and Institute of Physical and Chemical Research. Thu . "Comparison between the Gamow shell model and the cluster-orbital shell model for weakly bound systems". United States. doi:10.1103/PHYSREVC.75.034316.
@article{osti_20995129,
title = {Comparison between the Gamow shell model and the cluster-orbital shell model for weakly bound systems},
author = {Masui, H. and Kato, K. and Ikeda, K. and Department of Physics, Faculty of Science, Hokkaido University, Sapporo, 060-0810 and Institute of Physical and Chemical Research},
abstractNote = {We study contributions of poles and continua of the single-particle states to the wave function obtained by the cluster-orbital shell model (COSM). The COSM wave function is described in terms of a linear combination of nonorthogonal Gaussian basis sets. We study oxygen and helium isotopes as examples of normal and weakly bound nuclei. In the investigation of the contribution of the single-particle states, we expand the COSM wave function by using an extended completeness relation, which is constructed by the solution of the single-particle Hamiltonian. We use the complex scaling method to obtain the bound, resonant, and continuum states of the Hamiltonian and construct the extended completeness relation. The results are compared with those obtained by the Gamow shell model calculation.},
doi = {10.1103/PHYSREVC.75.034316},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • No abstract prepared.
  • The magnetic dipole moments of states in mirror pairs of the sd-shell nuclei and the strengths of the Gamow-Teller beta decays which connect them are compared with predictions based on mixed-configuration shell-model wave functions. From this analysis we extract the average effective values of the single-particle matrix elements of the l, s, and (Y/sup(/sup 2/)xs)/sup(/sup 1/) components of the M1 and Gamow-Teller operators acting on nucleons in the 0d/sub 5/2/, 1s/sub 1/2/, and 0d/sub 3/2/ orbits. These results are compared with the recent calculations by Towner and Khanna of the corrections to the free-nucleon values of these matrix elements whichmore » arise from the effects of isobar currents, mesonic-exchange currents, and mixing with configurations outside the sd shell.« less
  • We examine the validity of the [ital pn] quasiparticle RPA ([ital pn]QRPA) as a model for calculating [beta][sup +] and 2[nu][beta][beta] Gamow-Teller decays by making a comparison of the [ital pn]QRPA with a large-basis shell-model calculation within the 0[ital f]1[ital p] shell. We employ [ital A]=46 nuclei (those with six valence nucleons) for this comparison. Our comparison includes the decay matrix elements summed over final states, the strength distributions, and, for the first time, the coherent transition matrix elements (CTME). The [ital pn]QRPA overestimates the total [beta][sup +] and 2[nu][beta][beta] matrix elements. There are large differences in the shape ofmore » the spectra as well as in the CTME between the [ital pn]QRPA and shell-model results. Empirical improvements for the [ital pn]QRPA are discussed.« less
  • Gamma radiation and delayed neutrons following the decay of 44.9 ms /sup 29/Na have been studied in singles and coincidence mode with mass-separated sources. Evidence for a first excited state in /sup 29/Mg at 54.6 keV has been found, in good agreement with theoretical predictions. From the lifetime, tau = 1.83 +- 0.10 ns, deduced from ..gamma..-..gamma.. delayed coincidences with BaF/sub 2/ counters, a transition strength B(M1) = 0.11 Weisskopf units is found for the 55 keV (1/2/sup +/)..-->..g.s. ((3/2/sup +/) transition. A level scheme built on the new state at 55 keV and involving five new transitions has beenmore » established for bound levels in /sup 29/Mg. The features of these levels are compared with predictions of shell-model calculations, with which they substantially agree. In the neutron time-of-flight spectra, high-energy neutron branches have been found in addition to the previously reported decays. The observed distribution of the Gamow-Teller transition strengths with excitation energy for particle-unbound levels in /sup 29/Mg is found to be shifted upward by about 1 MeV relative to shell-model predictions.« less
  • Using the analogy with the problem of ionization and excitation of atoms in the propagation of relativistic charged particles through a bulk of matter, the process of Coulomb dissociation of weakly bound relativistic nuclei and hypernuclei is theoretically investigated in the framework of the two-cluster deuteron-like model. Explicit expressions for the total cross section of Coulomb disintegration of weakly bound systems are derived taking into account the corrections due to the finite size of a target nucleus. Numerical estimations for the Coulomb dissociation of relativistic hypernuclei {sup 3}H{sub {lambda}} and {sup 6}He{sub {lambda}} are performed. It is shown that, owingmore » to a sharp dependence of the Coulomb dissociation cross section on the binding energy, experimental measurements of the cross section allow one to determine the values of binding energy for these systems.« less