Observation of Low-LyingJπ=0+States in the Single-Closed-Shell NucleiPb192−198

First experimental evidence for a low-lying $J^{\pi }=0^{+}$ excited state in ${}_{}{}^{192-198}{}_{}{}^{}\mathrm{Pb}$ is obtained by study of the $\beta$ decay of mass-separated Bi isotopes. It is shown that such excited states correspond to deformed two-particle, two-hole configurations.