We report asymmetries in the forward-angle differential cross sections for pion single-charge-exchange scattering from oriented and unoriented ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$ nuclei. These asymmetries are directly related to the neutron deformation of a nucleus that has a large charge quadrupole moment. The measured asymmetry extrapolated to 0° is -0.020±0.024. In the model of Chiang and Johnson, this value implies a quadrupole deformation ratio ${\mathrm{\beta }}_2^{\mathit{n}}$/${\mathrm{\beta }}_2^{\mathit{p}}$=0.84±0.08, indicating that the excess neutrons are less deformed than the protons. This result conflicts with the predictions of the best available Hartree-Fock models based on Skyrme interactions. We also report on asymmetries of the nonresonant continuum and of the giant dipole resonances.

• Received 21 March 1994

DOI:https://doi.org/10.1103/PhysRevC.50.909