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Shape of the E1 Strength Function in the Region of Pygmy Anomaly Due to Non Statistical Background Coupling
- Source :
- Neutron Capture Gamma-Ray Spectroscopy ISBN: 9781461329428
- Publication Year :
- 1979
- Publisher :
- Springer US, 1979.
-
Abstract
- Systematic deviations from the Lorentzian approximation to the E1-giant dipole resonance (GDR) shape has been observed at the low energy side of the GDR /1,2/. The strength involved amounts to a few percent of the E1 sum rule,so this phenomenon is called pygmy resonance. A remarkable regularity has been mentioned by Lane /3/: The anomaly appears in mass number regions where empty single-particle states with l=0,1 are near the threshold. Applying the 1p-1h description the 1p-1h states containing the mentioned s or p-neutron particle states (threshold states) have unperturbed energies close to the energy of the anomaly. So these states may be saved from being coupled to the GDR. Such calculations /3,4,5/ performed in the pure 1p-1h shell model provide different amounts of the strength of the pygmy resonance as a function of the used residual interaction and basis.
Details
- ISBN :
- 978-1-4613-2942-8
- ISBNs :
- 9781461329428
- Database :
- OpenAIRE
- Journal :
- Neutron Capture Gamma-Ray Spectroscopy ISBN: 9781461329428
- Accession number :
- edsair.doi...........1a601da652a4f11b927cce3e7ce3210a