Population of0+States in Actinide andA≈190Nuclides by the (p,t) Reaction

The ($p,t$) reaction has been studied for targets of ${}_{}{}^{230,232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{234,236,238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{242,244}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$, ${}_{}{}^{182,184,186}{}_{}{}^{}\mathrm{W}$, and ${}_{}{}^{196}{}_{}{}^{}\mathrm{Pt}$. Uniformly strong (∼15% of ground-state cross section) transitions were found to populate excited $0^{+}$ states in all of the actinide nuclides. The observed $0^{+}$ states were previously known for five of the actinide nuclei, and in these cases the states were characterized by small $\alpha$-decay hindrance factors and large $E0\mathrm{}$ matrix elements. They have been previously classified as $\beta$ vibrations. The strong excitation of the $0^{+}$ states in the ($p,t$) reactions, combined with all other available evidence, suggests that throughout the actinide mass range these $0^{+}$ states represent a stable collective excitation different in character from both the $\beta$ vibration and the most common formulation of the pair vibration. No such excitations were seen in the W-Pt region.