The cross section of the isovector giant dipole resonance (GDR) excited by inelastic scattering of 120-MeV α particles for 0°≤Θα’≤3° has been measured using the (α,α’) and (α,α’) reactions. The results are compared with distorted-wave Born-approximation calculations with a GDR form factor depending on the relative difference of proton and neutron radii (Δ/). Within the model used, the Δ/ values for , , and deduced from the comparison of measured and calculated cross sections are (0.)%, (4.)%, and (3.0±1.3)%, respectively.
- Received 2 November 1990
©1991 American Physical Society