Dipole strength distributions in the stable Ba isotopes {sup 134-138}Ba: A study in the mass region of a nuclear shape transition

Journal Article · Fri Oct 01 04:00:00 EDT 2004 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.70.044319· OSTI ID:20695659

Scheck, M; Garrel, H von; Belic, D; Kneissl, U; Kohstall, C; Nord, A; Pitz, H H; Stedile, F ^[1]; Tsoneva, N ^[2]; Brentano, P von; Fransen, C; Gade, A; Jolie, J; Linnemann, A; Pietralla, N; Werner, V ^[3]; Stoyanov, C ^[4]

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1. Institut fuer Strahlenphysik, Universitaet Stuttgart, D-70569 Stuttgart (Germany)
2. Institut fuer Theor. Physik, Universitaet Giessen, D-35392 Giessen (Germany)
3. Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Cologne (Germany)
4. Institute for Nuclear Research and Nuclear Energy, 1784 Sofia (Bulgaria)

The low-lying dipole strength distributions in the odd-mass isotopes {sup 135,137}Ba were studied in nuclear resonance fluorescence experiments (NRF) performed at the Stuttgart Dynamitron facility using bremsstrahlung beams with end point energies of 4.1, 3.1, and 2.5 MeV. Numerous excited states, most of them unknown so far, were observed in the excitation energy range up to 4 MeV. Detailed spectroscopic information has been obtained on excitation energies, decay widths, decay branching ratios, and transition probabilities. The results for {sup 137}Ba are compared with calculations in the framework of the Quasiparticle-Phonon Model. The new data for {sup 135,137}Ba complete the systematics of low-lying dipole excitations as observed for the even Ba isotopes {sup 134,136,138}Ba in previous NRF experiments in Stuttgart. The complete systematics within the Ba isotopic chain, exhibiting a nuclear shape transition, is discussed with respect to E1 two-phonon excitations, M1 scissors mode excitations, and in regard to the new critical point symmetries.

• OSTI ID: 20695659
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 4 Vol. 70; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARIUM 134
BARIUM 135
BARIUM 137
BARIUM 138
BRANCHING RATIO
BREMSSTRAHLUNG
DIPOLES
DISTRIBUTION
EXCITATION
EXCITED STATES
MEV RANGE
NUCLEAR DECAY
PHONONS
PHOTON-NUCLEON INTERACTIONS
PROBABILITY
QUASIPARTICLE-PHONON MODEL
RESCATTERING
RESONANCE FLUORESCENCE
RESONANCE SCATTERING
SYMMETRY