Reexamined lifetimes of the low-lying states of 86 Zr by recoil distance differential decay measurements

摘要: The $^{86}\mathrm{Zr}$ nucleus, which has a low-lying level scheme characteristic of transitional presents, according to the existing electromagnetic transition data, subunitary ${\mathrm{B}}_{4/2}=B(E2,{4}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})/B(E2,{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ ratio, is anomalously low for nonmagic as it outside range traditional collective models values. In order check this anomaly, we performed new measurements lifetimes its states, with $\ensuremath{\gamma}$-ray coincident recoil distance Doppler shift method, using ROSPHERE detector array. New were determined positive-parity yrast states up ${10}^{+}$ one, and ${8}_{2}^{+},\phantom{\rule{0.16em}{0ex}}{5}_{1}^{\ensuremath{-}}$, ${7}_{1}^{\ensuremath{-}}$ states. newly values $B(E2)$ ${2}_{1}^{+}$ ${4}_{1}^{+}$ characterize nucleus moderate quadrupole deformation are well described by interacting boson model. ratio ${B}_{4/2}=1.38(22)$ no longer anomalous. value ${6}_{1}^{+}$ state indicates noncollective structure.