Showing papers by "R. F. Casten published in 2014"

Evidence for partial dynamical symmetries in atomic nuclei.

Abstract: Symmetries in nature offer very simple descriptions of complex systems. Partial Dynamical Symmetries (PDS) can considerably broaden their relevance. To present the first extensive test of a PDS for nuclei, we compare an SU(3) PDS to gamma to ground band $B(E2)$ values for 47 deformed nuclei. The parameter-free PDS is found to be quite successful, but with characteristic discrepancies, suggesting that symmetry remnants are more pervasive than heretofore realized. Furthermore, the SU(3) PDS gives new insights into collective models (e.g., interacting boson approximation). If these reproduce the PDS, they reflect finite size effects, while differences from the PDS point to SU(3) configuration mixing.

Investigation of 0+ states in mercury isotopes after two-neutron transfer

Abstract: Using the high-resolution Q3D magnetic spectrograph at the Maier-Leibnitz Laboratory (MLL) Tandem accelerator in Munich, we studied 0+ excitations in the mercury isotopes 198 Hg, 200 Hg, and 202 Hg after two-neutron transfer. We only observed 4-6 excited 0+ states per nucleus up to about 3-MeV excitation energy, far fewer than in other experiments of this (p, t ) campaign. The results reveal a sharp drop in the number of low-lying 0+ states towards the 208 Pb shell closure. We discuss the low-energy 0+ state density as a function of the valence nucleon number N val . The 0+ excitation energies and the measured (p, t ) transfer cross sections indicate a structural change throughout the Hg isotopes, with the most notable result being the peaking in the cross section of the low-lying excited 02 + state in 200 Hg.