Isoscalar giant dipole resonance in 208Pb via inelastic α scattering at 400 MeV and nuclear incompressibility

Abstract The isoscalar giant dipole resonance (ISGDR) in 208 Pb has been investigated with inelastic α -scattering of 400 MeV at extremely forward angles, including 0°. Energy spectra, virtually free from instrumental background, have been obtained and the ISGDR strength distribution has been extracted using a multipole-decomposition analysis (MDA). A difference-of-spectra approach yields the same ISGDR centroid energy as with MDA. These results lead to a value for nuclear incompressibility that is consistent for both the isoscalar dipole and monopole modes.