Investigation of0+states in198Hg after two-neutron pickup

Abstract

We studied ${0}^{+}$ states in ${}^{198}$Hg after the ${}^{200}$Hg${(p,t)}^{198}$Hg transfer reaction up to 3 MeV excitation energy. The experiment was performed using the high-resolution Q3D magnetic spectrograph at the Maier-Leibnitz Laboratory Tandem accelerator in Munich. In total, only four ${0}^{+}$ states were observed in ${}^{198}$Hg, significantly fewer than in other experiments of the $(p,t)$ transfer campaign. We discuss the low-energy ${0}^{+}$ state density as a function of the valence nucleon number ${N}_{\mathrm{val}}$ and test if the ${0}^{+}$ density can be used as a signature for the prolate-oblate shape-phase transition in the Hf-Hg region.