Low-lying E1 and M1 strengths in the deformed nucleus 160Gd☆

Abstract Measurements of the linear polarization of resonantly scattered photons have been used for model-independent parity determinations in nuclear resonance fluorescence experiments. The experiments have been performed at the bremsstrahlung facility of the Stuttgart Dynamitron accelerator. The use of two different Compton polarimeters, a five Ge-detector arrangement and a sectored single-crystal Ge-polarimeter enabled the parity assignments. Positive parities were established for a cluster of states near 3.3 MeV (M1 transitions) to be ascribed to the so-called scissors mode. In addition an enhanced electric dipole excitation near 2.5 MeV (2471 keV, B (E1) ↑ = 3.0 ± 0.4 × 10 −3 e 2 fm 2 ) has been observed as in the neighbouring isotopes 162 Dy and 150 Nd. These 1 − states systematically exhibit an uncommon decay branching hinting at K -mixing.