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Dipole strength distributions measured in unstable neutron-rich nuclei in the 132Sn mass region by utilizing relativistic Coulomb excitation of radioactive beams reveal a sizable fraction of "pygmy" strength below the giant dipole resonance. On the grounds of the RQRPA model, a strong linear correlation between the pygmy strength, parameters of the nuclear symmetry energy and the neutron skin thickness has been found. From the experimentally observed low-lying strength, the symmetry energy pressure p0 = 2.3 ± 0.8 MeV/fm³ and neutron skin thicknesses of 0.23 ± 0.04 fm in 130Sn and 0.24 ± 0.04 fm in 132Sn have been extracted. [ABSTRACT FROM AUTHOR]

Abstract: The ground-state structure of the near-drip-line nucleus 23O has been investigated in a one-neutron Coulomb breakup reaction. Differential cross sections for electromagnetic excitation of 23O projectiles (422 MeV/nucleon) incident on a lead target have been obtained from the measurement of the momenta of all breakup products including γ rays. The analysis of the deduced dipole-transition probability into the continuum infers a ground state configuration with a spectroscopic factor of 0.77(10) and thus a ground-state spin , resolving earlier conflicting experimental findings. Final-state interaction is of significant influence, an effective reduced scattering length for low-energy neutron scattering could be derived from the data. [Copyright &y& Elsevier]