Experimental investigation of nuclear double giant resonances
A survey over light to medium mass nuclei was made using the ({pi}{sup {minus}}, {pi}{sup +}) reaction at 295 MeV. The properties of the observed double giant dipole resonance are closely related via Coulomb displacement energy and isospin symmetry to those measured in the ({pi}{sup +},{pi}{sup {minus}}) reaction. This experiment provided a direct determination of the upper isospin component of the double giant dipole state, which is generally weak in the ({pi}{sup +},{pi}{sup {minus}}) reaction. The comparison of the ({pi}{sup {minus}},{pi}{sup +}) and ({pi}{sup +},{pi}{sup {minus}}) modes elucidates isospin splitting and the Pauli blocking effect. Data were also taken to elucidate the mechanism responsible for excitation of the analog of the anti-analog. Inferences are made on the range of the pion double charge exchange operator at 295 and 50 MeV. Also, the excitation function for the giant dipole built on the isobaric analog state was measured using the {sup 13}C({pi}{sup +},{pi}{sup {minus}}){sup 13}O reaction. This was the first attempt to measure the excitation function of a double giant resonance. The data shows the first evidence for a double resonance involving spin-flip.
- Research Organization:
- Univ. of Texas, Austin, TX (United States)
- OSTI ID:
- 102589
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: 1993
- Country of Publication:
- United States
- Language:
- English
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