Centrifugal stretching from lifetime measurements in the170Hf ground state band

Abstract

Centrifugal stretching in the deformed rare-earth nucleus ${}^{170}$Hf is investigated using high-precision lifetime measurements, performed with the New Yale Plunger Device at Wright Nuclear Structure Laboratory, Yale University. Excited states were populated in the fusion-evaporation reaction ${}^{124}$Sn(${}^{50}$Ti,4n)${}^{170}$Hf at a beam energy of 195 MeV. Recoil distance doppler shift data were recorded for the ground state band through the $J={16}^{+}$ level. The measured $B(E2)$ values and transition quadrupole moments improve on existing data and show increasing $\ensuremath{\beta}$ deformation in the ground state band of ${}^{170}$Hf. The results are compared to descriptions by a rigid rotor and by the confined $\ensuremath{\beta}$-soft rotor model.