Probing the E2 properties of the scissors mode with real photons

The study of the properties of the nuclear scissors mode provides an essential insight into the nature of the restoring forces between the proton and neutron subsystems. Recently, first information on the E2 decay transition strength of the scissors mode was extracted from a high-statistics photon-scattering experiment on ¹⁵⁶Gd using quasi-monochromatic photon beams provided by the High Intensity γ-ray Source (HIγS). The data allowed for measuring a finite value of the E2/M1 multipole mixing ratio and, thus, the first measurement of an F-vector E2 transition in axially deformed nuclei. A similar continuative experiment has been performed on the well-deformed nuclei ^162,164Dy at HIγS. The obtained results indicate that highest-precision photon-scattering experiments with linearly polarized photons are highly sensitive to the electric quadrupole-decay properties of the scissors mode. The obtained results are presented in detail and discussed in terms of the underlying nuclear physics. An outlook for future research is given.