Spin and parity assignments to dipole excitations of the odd-mass nucleus ²⁰⁷Pb from nuclear resonance fluorescence experiments with linearly-polarized γ-ray beams

Pb(γ,γ′) photon scattering reactions were studied [1] with the nearly monochromatic, linearly polarized photon beams at the High Intensity γ-ray Source (HIγS) at the DFELL. Azimuthal scattering intensity asymmetries measured with respect to the polarization plane of the beam have been used for the first time to assign both the spin and parity quantum numbers of dipole excited states of ²⁰⁶,²⁰⁷,²⁰⁸Pb at excitation energies in the vicinity of 5.5 MeV. Evidence for dominant particle-core coupling is deduced from these results along with information on excitation energies and electromagnetic transition matrix elements.