Giant Resonances in the High-Energy Helium Inelastic Scattering

Abstract

An analysis of earlier reported cross-section data from ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(\alpha , {\alpha }^{\prime })$, (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$'), and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$') reactions at $E_{\alpha }=90\mathrm{}$ MeV and $E_{{}_{}{}^3{}_{}{}^{}\mathrm{He}}=75\mathrm{}$ MeV confirms the discovery of a new giant resonance at $E^{*}\approx 11$ MeV in heavy nuclei. From the magnitude of the cross sections and theoretical sum-rule prescriptions, it is found that the resonance may be interpreted as a giant-quadrupole state but not, as recently suggested, a giant-monopole state.