Isomer-selected decay of the GDR in 156Dy∗

Abstract The strength distribution of high-energy γ-rays emitted in the statistical decay of the 156 Dy ∗ compound nucleus, with E ∗ = 92.5 MeV , has been measured inclusively and for selected decay pathways in which isomers in 149 Dy, 151 Dy and 152 Dy were populated. For both spectra a deformation | β | = 0.3 is deduced and the centroid energies agree with those found from ground-state systematics. The high-energy γ-ray spectrum triggered on isomeric decay shows an increase of the width of the GDR in comparison with the inclusive spectrum.