Single-neutron states in ${}^{133}\mathrm{Sn}$ and ${}^{209}\mathrm{Pb}$, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the (${}^9\mathrm{Be}$, ${}^8\mathrm{Be}$) one-neutron transfer reaction in inverse kinematics using particle-$\gamma$ coincidence spectroscopy. In addition, the $s_{1/2}$ single-neutron hole-state candidate in ${}^{131}\mathrm{Sn}$ was populated by (${}^9\mathrm{Be}$, ${}^{10}\mathrm{Be}$). Doubly closed-shell ${}^{132}\mathrm{Sn}$ (radioactive) and ${}^{208}\mathrm{Pb}$ (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, $\gamma$-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the $3p_{1/2}$ candidate in ${}^{133}\mathrm{Sn}$, new absolute cross sections for the $1h_{9/2}$ candidate in ${}^{133}\mathrm{Sn}$ and $3s_{1/2}$ candidate in ${}^{131}\mathrm{Sn}$, and new lifetimes for excited states in ${}^{133}\mathrm{Sn}$ and ${}^{209}\mathrm{Pb}$. This is the first report on excited-state lifetimes of ${}^{133}\mathrm{Sn}$, which allow for a unique test of the nuclear shell model and ${}^{132}\mathrm{Sn}$ double-shell closure.

• Received 4 February 2014

DOI:https://doi.org/10.1103/PhysRevLett.112.172701