Abstract
We have measured the cross sections and the analyzing powers for the reaction for proton energies from 4.0 to 16.2 MeV. The corresponding range in excitation energies, 13.94 to 25.33 MeV, covers the region of the giant dipole resonance in . The five-angle angular distributions measured with unpolarized and with polarized beams at eight energies over this region were analyzed to determine the magnitudes and relative phases of the transition matrix elements. The analysis included , , and transitions. The observed strength exhausts only about 6% of the classical dipole sum rule. The dominant strength is compared to a shell-model calculation which includes 3p-3h excitations. A fairly uniform distribution of strength is observed which exhausts about 7% of the total energy-weighted sum rule. Although large uncertainties on this result could allow the existence of a giant resonance, the most probable values indicate that no appreciable concentration of strength is observed.
NUCLEAR REACTIONS ; measured , MeV; measured and , MeV. deduced -matrix amplitudes and phases. Compared strength to energy-weighted sum rule. Compared strength to shell-model calculation. Enriched targets.
- Received 27 August 1975
DOI:https://doi.org/10.1103/PhysRevC.13.922
©1976 American Physical Society