The 156Dy(p, t),154Dy reaction was studied, using 20 MeV protons and a magnetic spectrograph to analyze the reaction products. This reaction on the "deformed" target 156Dy has three strong L = 0 transitions populating levels in the "spherical" nucleus 154Dy at 0, 661, and 1058 keV with relative strengths of 100:74:16, respectively. This population pattern is similar to those observed in the isotones 152Gd and,150Sm, in which the third 0+ bands have been interpreted as deformed bands coexisting in spherical nuclei. However, the third 0+ band in 154Dy has a rotational energy spacing as large as that for the ground-state band, which suggests that it does not have a large deformation, and its (p, t) strength is significantly less than those for the corresponding states in the samarium and gadolinium isotones. This restricts the shape-coexistence interpretation of excited 0+ states in 154Dy. The systematics suggest that,152Gd is probably also not as good an example of shape coexistence as 150Sm.
Short-range Lifetime Measurements for Deep-inelastic Reaction Products: the \(^{19}\)O Test Case
