Lifetimes and electromagnetic transition strengths in Dy-155

Recoil distance Doppler-shift and Doppler-shift attenuation lifetime measurements were carried out for levels in Dy-155 through the coincident detection of. rays. Twenty-six lifetimes, most of them for the first time, were determined using the differential decay curve method for the analysis of the data. At low and medium spins, particle-plus-triaxial-rotor calculations reveal different quadrupole deformations for the one-quasineutron bands in this transitional nucleus. At high spin, the reduced B(E2) transition probabilities confirm with a better precision the results of a previous study implying decreased collectivity with increasing spin.