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Title: Possible E(5/4) Symmetry in 135Ba

Abstract

The nucleus 135Ba is investigated as a possible candidate for E(5/4), a non-trivial example of critical point symmetry in odd mass nuclei, for the case of a liquid drop with quadrupole deformation coupled to a particle with j = 3/2.

Authors:
 [1];  [2];  [3];  [4];  [3];  [5];  [2]
  1. Department of Physics, University of Richmond, Richmond, VA 23173 (United States)
  2. (United States)
  3. Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States)
  4. (Turkey)
  5. SERC Daresbury Laboratory, Warrington WA44AD (United Kingdom)
Publication Date:
OSTI Identifier:
20719731
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 802; Journal Issue: 1; Conference: ENS'05: International symposium on exotic nuclear systems, Debrecen (Hungary), 20-25 Jun 2005; Other Information: DOI: 10.1063/1.2140665; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BARIUM 135; LIQUID DROP MODEL; MASS; QUADRUPOLES; SYMMETRY

Citation Formats

Fetea, M.S., Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520, Cakirli, R.B., Department of Physics, University of Istanbul, Istanbul, Casten, R.F., Warner, D.D., and Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520. Possible E(5/4) Symmetry in 135Ba. United States: N. p., 2005. Web. doi:10.1063/1.2140665.
Fetea, M.S., Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520, Cakirli, R.B., Department of Physics, University of Istanbul, Istanbul, Casten, R.F., Warner, D.D., & Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520. Possible E(5/4) Symmetry in 135Ba. United States. doi:10.1063/1.2140665.
Fetea, M.S., Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520, Cakirli, R.B., Department of Physics, University of Istanbul, Istanbul, Casten, R.F., Warner, D.D., and Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520. Mon . "Possible E(5/4) Symmetry in 135Ba". United States. doi:10.1063/1.2140665.
@article{osti_20719731,
title = {Possible E(5/4) Symmetry in 135Ba},
author = {Fetea, M.S. and Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 and Cakirli, R.B. and Department of Physics, University of Istanbul, Istanbul and Casten, R.F. and Warner, D.D. and Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520},
abstractNote = {The nucleus 135Ba is investigated as a possible candidate for E(5/4), a non-trivial example of critical point symmetry in odd mass nuclei, for the case of a liquid drop with quadrupole deformation coupled to a particle with j = 3/2.},
doi = {10.1063/1.2140665},
journal = {AIP Conference Proceedings},
number = 1,
volume = 802,
place = {United States},
year = {Mon Nov 21 00:00:00 EST 2005},
month = {Mon Nov 21 00:00:00 EST 2005}
}
  • Evidence for the first empirical example of a transitional dynamical symmetry at a critical point is discussed in the spectrum of {sup 134}Ba . The role of such classes of symmetries in nuclear structural evolution is also discussed.
  • The first case of a Bose-Fermi critical point symmetry, E(5/4), representing the coupling of a j=3/2 fermion to an E(5) core, was recently proposed. Since {sup 134}Ba has been found to be an empirical manifestation of E(5), we carried out a {beta}-decay experiment to study levels in {sup 135}Ba, where the last neutron can occupy the 2d{sub 3/2} orbit, as the first test of E(5/4). The comparison shows significant areas of agreement as well as significant discrepancies. Comparison of interacting boson-fermion approximation and shell model calculations with the data are also presented.
  • A {gamma}-rigid solution of the Bohr Hamiltonian for {gamma} = 30 deg. is derived, its {beta}-part being related to the second order Casimir operator of the Euclidean algebra E(4). The solution is called Z(4), since it corresponds to the Z(5) model with the {gamma} variable 'frozen'. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are in close agreement to the E(5) critical point symmetry, as well as to experimental data in the Xe region around A = 130.
  • There has been intense recent interest in equilibrium shape / phase transitions in nuclei and the concept of critical point symmetries to describe them. The first critical point symmetry for an odd-mass nucleus has been recently proposed, namely, the E(5/4) Bose-Fermi critical point symmetry, it corresponds to coupling between an odd particle in a j = 3/2 orbit and the E(5) critical point symmetry, at the transition between the O(6) gamma-soft and the U(5) vibrator symmetries. Since 134Ba is a candidate for the E(5) critical point symmetry, we carried out a {beta}-decay experiment on 135Ba whose last neutron can occupymore » a 2d3/2 orbit as a first test of E(5/4). The experimental results were compared to E(5/4) and also with the Interacting Boson-Fermion Approximation Model (IBFA) and Shell Model calculations. We see fair agreement with E(5/4) for B(E2) values but not for all energies. The IBFA shows better agreement with data than E(5/4) and the Shell model shows the best agreement.« less
  • We have measured the ({sup 3}H+{ital p}) and ({sup 3}He+{ital n}) breakup of {sup 4}He by {sup 4}He({ital e},{ital e}{prime}{ital c}) coincidence experiments at low momentum transfer ({ital q}{approx}0.39 fm{sup {minus}1}) in the excitation energy region 22{le}{ital E}{sub {ital x}}{le}36 MeV. Both channels were studied simultaneously by detecting the charged fragments {ital c}={ital p}, {sup 3}H, and {sup 3}He in the same detector system. The measured {sup 4}He({ital e},{ital e}{prime}{ital p}){sup 3}H and {sup 4}He({ital e},{ital e}{prime}{ital n}){sup 3}He angular correlations as well as the deduced total {sup 4}He({ital e},{ital e}{prime}{ital p}){sup 3}H and {sup 4}He({ital e},{ital e}{prime}{ital n}){sup 3}Hemore » cross sections are reproduced by microscopic model calculations with a charge-symmetric nuclear Hamiltonian.« less