New excited 2 + and 3 − two-proton states in Po 126 84 210 populated by two-proton transfer

Five new ${2}^{+}$ levels have been established in the semimagic $^{210}\mathrm{Po}$ nucleus from a $^{208}\mathrm{Pb}(^{12}\mathrm{C},^{10}\mathrm{Be}$) two-proton transfer experiment, performed at energies close to the Coulomb barrier at JAEA Tokai. A setup combining Ge, ${\mathrm{LaBr}}_{3}$, and Si telescopes was used to detect both in-beam $\ensuremath{\gamma}$ rays and ejectile residues. The new ${2}^{+}$ states have been established by means of the transitions toward the ${0}^{+}$ ground state which are present in the $\ensuremath{\gamma}$ spectra produced by properly selecting the excitation energy in $^{210}\mathrm{Po}$ after kinematical reconstruction. ${({f}_{7/2})}^{2}$, ${h}_{9/2}\ensuremath{\bigotimes}{f}_{5/2}$, ${({i}_{13/2})}^{2}$, ${f}_{7/2}\ensuremath{\bigotimes}{p}_{3/2}$, and ${f}_{7/2}\ensuremath{\bigotimes}{f}_{5/2}$ two-proton configurations are assigned to these states. In addition, a new ${3}^{\ensuremath{-}}$ level has also been established in this nucleus, very likely originating from the ${f}_{7/2}\ensuremath{\bigotimes}{i}_{13/2}$ configuration. Shell-model calculations strongly support these assignments.