Study of $0^+$ States and Collectivity in $^{154}$\textrm{Gd} by the (p,t$\gamma$) Reaction

Recent experiments [1] have revealed an unusual number of low-lying $0^+$ states ($<$~3~MeV) in a number of rare-earth nuclei, including $^{154,156}$\textrm{Gd}. Indeed, the structure of these and neighboring ($N\sim90$) nuclei have been of recent interest [2]. To investigate the decay and population of these $0^+$ states, an experiment was conducted at the 88" cyclotron at LBNL using the STARS and LiBerACE detector arrays. A 25~MeV proton beam incident onto a $^{156}$\textrm{Gd} target was used to populate states in $^{154}$\textrm{Gd} by the (p,t$\gamma$) reaction and $^{156}$\textrm{Gd} by (p,p'$\gamma$). The exit channel of the reaction and the residual excitation energy of the nucleus were tagged by detecting scattered charged particles in a \textrm{Si} telescope array (STARS) while coincident $\gamma$ rays were detected using 6 \textrm{Ge} clovers and 1 \textrm{Ge} LEPS detector of the LiBerACE array. Branching ratios, population distributions, and particle-$\gamma$ correlations are used to probe the nature of $0^+$ states and collectivity in $^{154}$\textrm{Gd}.Preliminary results are presented. DE-FG52-06NA26206 (UR), DE-AC52-07NA27344 (LLNL), and DE-AC02-05CH11231 (LBNL).\\ {[1]}S.R.~Lesher, \textit{et~al.}, Phys. Rev. C \textbf{66}, 051305 (2002);D.A.~Meyer, \textit{et~al.}, Phys. Rev. C \textbf{74}, 044309(2006).\\ {[2]}W.D.~Kulp, \textit{et~al.}, Phys. Rev. Lett. \textbf{91}, 102501(2003);W.D.~Kulp, \textit{et~al.}, Phys. Rev. C \textbf{77}, 061301(2008).