New Giant Resonances in 172-MeVαScattering fromPb208

Abstract
Spectra of 172-MeV α scattering from Pb208 indicate in addition to giant monopole and quadrupole excitation new giant resonance structures in hadron scattering at Ex=17.5±0.8 and 21.3±0.8 MeV with corresponding widths of 4.8±0.8 and 5.9±0.8 MeV. The angular distributions indicate L=3 and 1 giving rise to an interpretation as isoscalar giant octupole resonance (17.5 MeV, 60% energy-weighted sum-rule strength), and isoscalar giant dipole resonance (21.3 MeV, 90% energy-weighted sum-rule strength).