Spectroscopy ofCe140andCe138via theCe140(p, p′),Ce142(p, t), andCe140(p, t)reactions atEp=30MeV

Abstract

The nuclei $^{138,140}\mathrm{Ce}$ have been studied by means of the $^{140}\mathrm{Ce}(p, t)$, $^{142}\mathrm{Ce}(p, t)$, and $^{140}\mathrm{Ce}(p, {p}^{\ensuremath{'}})$ reactions at 30 MeV. Angular distributions have been measured from ${\ensuremath{\theta}}_{\mathrm{lab}}=16\ifmmode^\circ\else\textdegree\fi{} \mathrm{to} 64\ifmmode^\circ\else\textdegree\fi{}$. The inelastic scattering data were analyzed with distorted-wave Born approximation to confirm multipolarities and extract deformation parameters for the strongly excited levels. The ($p, t$) data were also analyzed with distorted-wave Born approximation to obtain limits on the two-nucleon orbital angular momentum ($L$) transfer. This analysis, plus the empirical angular distribution shapes of levels with known ${J}^{\ensuremath{\pi}}$, permits us to suggest (or at least limit) ${J}^{\ensuremath{\pi}}$ values for many new levels. The ($p, t$) differential cross sections have been further analyzed in terms of simple two-neutron configurations through the enhancement factor concept. The two-neutron transfer results are discussed in terms of the pair vibration model.NUCLEAR REACTIONS $^{142,140}\mathrm{Ce}(p, t)$, $^{140}\mathrm{Ce}(p, {p}^{\ensuremath{'}})$, ${E}_{p}=30$ MeV; measured level energies and $\ensuremath{\sigma}(\ensuremath{\theta})$; DWBA analysis, deformation parameters, enhancement factors.