Fragmentation and systematics of the pygmy dipole resonance in the stable N=82 isotones

Journal Article · Mon Aug 15 00:00:00 EDT 2011 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.84.024326· OSTI ID:21596662

Savran, D; Loeher, B ^[1]; Elvers, M; Endres, J; Zilges, A ^[2]; Fritzsche, M; Pietralla, N; Ponomarev, V Yu; Romig, C; Schnorrenberger, L ^[3]; Sonnabend, K ^[4]

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1. ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany)
2. Institut fuer Kernphysik, Universitaet zu Koeln, Zuelpicher Strasse 77, D-50937 Koeln (Germany)
3. Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany)
4. Institut fur Angewandte Physik, Goethe-Universitaet Frankfurt, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany)

The low-lying electric dipole (E1) strength in the semimagic nucleus {sup 136}Xe has been measured, which finalizes the systematic survey to investigate the so-called pygmy dipole resonance (PDR) in all stable even N=82 isotones with the method of nuclear resonance fluorescence using real photons in the entrance channel. In all cases, a fragmented resonance-like structure of E1 strength is observed in the energy region 5-8 MeV. An analysis of the fragmentation of the strength reveals that the degree of fragmentation decreases toward the proton-deficient isotones, while the total integrated strength increases, indicating a dependence of the total strength on the neutron-to-proton ratio. The experimental results are compared to microscopic calculations within the quasiparticle phonon model. The calculation includes complex configurations of up to three phonons and is able to reproduce also the fragmentation of the E1 strength, which allows us to draw conclusions on the damping of the PDR. Calculations and experimental data are in good agreement on the degree of fragmentation and also on the integrated strength if the sensitivity limit of the experiments is taken into account.

• OSTI ID: 21596662
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 84, Issue 2; Other Information: DOI: 10.1103/PhysRevC.84.024326; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CONFIGURATION
DAMPING
E1-TRANSITIONS
ELECTRIC DIPOLES
ISOTONIC NUCLEI
MAGIC NUCLEI
MEV RANGE 01-10
NEUTRONS
PHONONS
PROTONS
QUASIPARTICLE-PHONON MODEL
RESONANCE
RESONANCE FLUORESCENCE
SENSITIVITY
XENON 136
BARYONS
DIPOLES
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
FERMIONS
FLUORESCENCE
HADRONS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LUMINESCENCE
MATHEMATICAL MODELS
MEV RANGE
MULTIPOLE TRANSITIONS
MULTIPOLES
NUCLEAR MODELS
NUCLEI
NUCLEONS
PHOTON EMISSION
QUASI PARTICLES
STABLE ISOTOPES
XENON ISOTOPES