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

The isoscalar giant dipole resonance (ISGDR) in Pb-208 has been investigated with inelastic a-scattering of 400 MeV at extremely forward angles, including 0degrees. 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. (C) 2003 Elsevier Science B.V All rights reserved.