Admixture of the giant dipole resonance to low lying 1−-states in heavy nuclei

Abstract

An investigation of E1 transitions from low lying Jπ=1− states detected in (e,e′) and (γ,γ′) measurements is presented. The B(E1) strengths are discussed in terms of the admixture of the giant dipole resonance to the low lying octupole states. We show that the spreading widths Γ ↓ are around 20–50 keV in the examined A=142–238 nuclei and compare this result with spreading widths extracted from isospin mixing matrix elements of isobaric analog resonances.