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Title: Study of {beta}-Decay in the Proton-Neutron Interacting Boson-Fermion Model

Abstract

We study {beta}-decay in odd-A nuclei together with the energy levels and other properties in the proton-neutron interacting-boson-fermion model. We also report on the preliminary results in the odd-odd nuclei in the proton-neutron interacting boson-fermion-fermion model.

Authors:
 [1];  [2];  [3];  [4]
  1. Dipartimento di Fisica dell'Universita di Milano, Via Celoria 16, Milan 20133 (Italy)
  2. (Italy)
  3. Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia)
  4. Faculty of Informatics, Kansai University, Takatsuki 569-1095 (Japan)
Publication Date:
OSTI Identifier:
20798630
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 831; Journal Issue: 1; Conference: International conference on frontiers in nuclear structure, astrophysics, and reactions - FINUSTAR, Isle of Kos (Greece), 12-17 Sep 2005; Other Information: DOI: 10.1063/1.2201016; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; APPROXIMATIONS; BETA DECAY; ENERGY LEVELS; INTERACTING BOSON MODEL; NEUTRONS; ODD-ODD NUCLEI; PROTONS

Citation Formats

Zuffi, L., Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, Milan 20133, Brant, S., and Yoshida, N. Study of {beta}-Decay in the Proton-Neutron Interacting Boson-Fermion Model. United States: N. p., 2006. Web. doi:10.1063/1.2201016.
Zuffi, L., Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, Milan 20133, Brant, S., & Yoshida, N. Study of {beta}-Decay in the Proton-Neutron Interacting Boson-Fermion Model. United States. doi:10.1063/1.2201016.
Zuffi, L., Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, Milan 20133, Brant, S., and Yoshida, N. Wed . "Study of {beta}-Decay in the Proton-Neutron Interacting Boson-Fermion Model". United States. doi:10.1063/1.2201016.
@article{osti_20798630,
title = {Study of {beta}-Decay in the Proton-Neutron Interacting Boson-Fermion Model},
author = {Zuffi, L. and Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, Milan 20133 and Brant, S. and Yoshida, N.},
abstractNote = {We study {beta}-decay in odd-A nuclei together with the energy levels and other properties in the proton-neutron interacting-boson-fermion model. We also report on the preliminary results in the odd-odd nuclei in the proton-neutron interacting boson-fermion-fermion model.},
doi = {10.1063/1.2201016},
journal = {AIP Conference Proceedings},
number = 1,
volume = 831,
place = {United States},
year = {Wed Apr 26 00:00:00 EDT 2006},
month = {Wed Apr 26 00:00:00 EDT 2006}
}
  • We have studied the levels of {sup 140}La populated in the beta decay of {sup 140}Ba by gamma-ray spectroscopy, which included Compton-suppression gamma-ray spectra of {sup 140}Ba sources that were continuously eluted of the {sup 140}La daughter activity using ion-exchange chromatographic techniques. The study of the gamma-ray deexcitation of the low-energy levels was completed by a measurement of the low-energy gamma-ray spectrum following thermal neutron capture on {sup 139}La. Also, we have performed calculations using the interacting-boson-fermion-fermion model. When we compare the model predictions with the levels and their properties, which we have determined, we find better agreement than hasmore » been obtained using quasiparticle-vibrational models.« less
  • We have investigated the odd-[ital A] Tc isotopes in the mass 100 region using the neutron-proton interacting boson-fermion model. The calculation is based on the validity of the [ital Z]=38 subshell closure. The results for the energy spectra and electromagnetic transitions are compared with experimental data and with results from other calculations which considered [ital Z]=50 as a valid closed shell for Tc isotopes.
  • We investigate the structure of the intrinsic states for the symmetric and antisymmetric {beta} vibrations in the O(6) limit of the neutron-proton interacting boson model and of the low-lying configurations projected from these intrinsic states. We study the decay modes of these low-lying states, particularly the antisymmetric 0{sup +} state. This level appears to decay only to the 1{sup +} and 2{sup +} mixed-symmetry states. The signature for these decays is that the {ital M}1 and {ital E}2 strengths go to zero for {ital N}{sub {pi}}={ital N}{sub {nu}}.
  • The interacting boson-fermion-fermion model approach to {beta} decay is applied to the decay from the even-even {sup 124}Ba to the odd-odd {sup 124}Cs nucleus. The theoretical results for energy levels, electromagnetic properties and {beta} decay rates are compared with experimental data for {sup 124}Cs. The calculated {beta}-decay rates demonstrate that the interacting boson approximation can be applied in the description of {beta} decays from even-even to odd-odd nuclei.
  • The interacting boson-fermion model is used to analyze beta decay. The beta transition operator in the boson-fermion space is constructed with the parameters obtained from microscopic considerations. The ft values are calculated for the first nonunique forbidden transitions between states based on natural parity orbitals in the decays of /sup 195/Ir..-->../sup 195/Pt, /sup 195/Au..-->../sup 195/Pt, /sup 195/Hg..-->../sup 195/Au, /sup 197/Pt..-->../sup 197/Au, and /sup 197/Hg..-->../sup 197/Au. The structure of the odd-neutron nuclei is described in the U(6)xU(12) boson-fermion symmetry limit. For the odd-proton nuclei, three different approaches, in particular the U(6)xU(4) symmetry, the U(6)xU(20) symmetry, and the perturbed U(6)xU(4) scheme, aremore » compared. The calculated ft values are very sensitive to details of nuclear wave functions, the best results being obtained with the perturbed U(6)xU(4) scheme. Phase ambiguities in nuclear wave functions can be disentangled from beta decay analysis. The exchange terms in the boson-fermion transition operator, which take into account the Pauli principle between the odd-nucleon and nucleons forming the even-even collective core, proved to be quite important.« less