Low-energy structure of the even-A 96−104 Ru isotopes via g-factor measurements

The transient-field-perturbed angular correlation technique was used with Coulomb excitation in inverse kinematics to perform a systematic measurement of the g factors of the first excited 21+ states in the stable even-A isotopes Ru96-104. The measurements have been made relative to one another under matched kinematic conditions and include a measurement of g(21+)=+0.47(3) in Ru96

Deformation crossing near the first-order shape-phase transition in 152-156 Gd

Quantitative evidence of the spherical-to-deformed shape phase transition near N=90 is given using the model-independent quadrupole shape invariant q2, which provides a measure of the ? deformation of a given nucleus. This shape invariant is obtained using experimental B(E2) values for the ground state band and first excited 0+ band of Gd isotopes around N=90, and is compared to calculations within the interacting boson model. Near the shape phase transition, the ground and excited 0+ band deformations are observed to cross. � 2008 The American Physical Society

Regularities and symmetries of subsets of collective 0 + states

The energies of subsets of excited 0+ states in geometric collective models are investigated and found to exhibit intriguing regularities. In models with an infinite square well potential, it is found that a single formula, dependent on only the number of dimensions, describes a subset of 0+ states. The same behavior of a subset of 0+ states is seen in the large boson number limit of the interacting boson approximation (IBA) model near the critical point of a first-order phase transition, in contrast to the fact that these 0+ state energies exhibit a harmonic behavior in all three limiting symmetries of the IBA. Finally, the observed regularities in 0+ energies are analyzed in terms of the underlying group theoretical framework of the different models. � 2009 The American Physical Society

β decay spectroscopy of light Nd isotopes

Excited states in 132,134Nd were populated in the ?+/? decay of 132,134Pm and studied through off-beam ?-ray spectroscopy. Level spins and multipole mixing ratios of transitions were determined through an angular correlation analysis. In 132Nd, a new excited 0+ state is identified and in 134Nd the level scheme is significantly extended. Differences in the location of the 02+ state and the ? bandhead above and below N=82 suggest that the lighter isotopes are much more ?-soft than the heavier Nd and that a first-order phase transitional description is not applicable in the N<82 region. � 2013 American Physical Society

β decay spectroscopy of light Nd isotopes

Excited states in 132,134Nd were populated in the β+/ε decay of 132,134Pm and studied through off-beam γ-ray spectroscopy. Level spins and multipole mixing ratios of transitions were determined through an angular correlation analysis. In 132Nd, a new excited 0+ state is identified and in 134Nd the level scheme is significantly extended. Differences in the location of the 02+ state and the γ bandhead above and below N=82 suggest that the lighter isotopes are much more γ-soft than the heavier Nd and that a first-order phase transitional description is not applicable in the

First experimental test of X(5) critical-point symmetry in the A ∼ 130 mass region: Low-spin states and the collective structure of 130 Ce

Excited, low-spin states in Ce130 are populated in the ?+/? decay of Pr130 and studied through off-beam ?-ray spectroscopy at the Yale moving tape collector. New coincidence data lead to the construction of a substantially revised level scheme. The low-lying states of Ce130 are compared with the predictions of the X(5) critical-point model and the X(5)-?4 model, and the latter is found to give better agreement with the data in terms of energies. Discrepancies in the relative B(E2) values in Ce130 and the geometrical models suggest that the ? degree of freedom may play an important role in this mass region. � 2008 The American Physical Society

g factor of the 2 + 1 state of 168 Hf

The g factor of the 21+ state of 168Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(21+)=0.17(3), is discussed in relation to the systematics of the previously reported g factors in th