Measurements of relative differential cross sections have been obtained for elastic scattering of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ nuclei from ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ at energies well below the Coulomb barrier. The measurements show deviations from Rutherford scattering, which are attributed to electric polarization of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ nuclei in the Coulomb field of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. The deduced value of the electric polarizability for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is α=0.250±0.040 ${\mathrm{fm}}^3$. This result is significantly larger than expected from measurements of cross sections for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ photodisintegration.

• Received 30 July 1990

DOI:https://doi.org/10.1103/PhysRevC.43.66