Evidence for Different Proton and Neutron Deformations in Heavy Nuclei Deduced from Polarized-Deuteron Scattering

Abstract

Inelastic scattering of vector polarized deuterons near ${E}_{d}=20$ MeV has been measured for a series of target nuclei ranging from the $\mathrm{sd}$ shell to $^{232}\mathrm{Th}$. Isoscalar transition rates deduced from a collective-model analysis are found to be in agreement with the corresponding electromagnetic quantities for the quadrupole and octupole excitations of $T=0$ nuclei and of $^{208}\mathrm{Pb}$. For the quadrupole excitation in $^{144}\mathrm{Sm}$, $^{152}\mathrm{Sm}$, $^{154}\mathrm{Sm}$, and $^{232}\mathrm{Th}$ about 20% smaller values are obtained, which imply a larger proton than neutron deformation for these nuclei.