Experimental Studies of Pdr and Gdr in Exotic Nuclei

The dipole response of exotic nuclei can be ideally studied using Coulomb excitation in inverse kinematics, enabling the investigation of excitation energies spanning the pygmy (PDR) and giant dipole resonance (GDR). The electric dipole polarizability αD, being very sensitive to the low-lying dipole strength, is correlated to the neutron skin thickness in a robust and less model-dependent manner [1]. Recently, for the stable nucleus, Pb the neutron skin thickness was extracted from the measured αD [2]. The extend of model-dependency for these kind of correlations is under discussion, e.g. as detailed by X. Roca-Maza [3].