Measurement of charge-density differences in the interior of Pb isotopes.

The ground-state charge densities of /sup 204,206,207,208/Pb have been accurately determined by elastic electron scattering. Mean-field calculations fail to describe the individual charge densities in the central region of the nucleus. However, they properly account for polarization mechanisms in the nuclear interior, as they accurately describe the corresponding charge-density differences. We show that these data are sensitive to the value of the nuclear compressibility kappa and that they are compatible with the value kappa = 230 MeV.