A revised $B(E2;2_1^{+}\to 0_1^{+})$ value in the semi-magic nucleus ${}^{210}$Po

Abstract

The lifetimes of the $2_1^{+}$, the $2_2^{+}$ and the $3_1^{-}$ states of ${}^{210}$Po have been measured in the ${}^{208}$Pb(${}^{12}$C,${}^{10}$Be)${}^{210}$Po transfer reaction by the Doppler-shift attenuation method. The results for the lifetime of the $2_1^{+}$ state is about three times shorter than the adopted value. However, the new value still does not allow for consistent description of the properties of the yrast $2_1^{+}$, $4_1^{+}$, $6_1^{+}$, and $8_1^{+}$ states of ${}^{210}$Po in the framework of nuclear shell models. The Quasi-particle Phonon Model (QPM) calculations also cannot overcome this problem thus indicating the existence of a peculiarity which is neglected in both theoretical approaches.