We report asymmetries in the forward-angle differential cross sections for pion single-charge-exchange scattering from oriented and unoriented Ho165 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 -0.0200.024. In the model of Chiang and Johnson, this value implies a quadrupole deformation ratio 2n/2p=0.840.08, 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.
ASJC Scopus subject areas
- Nuclear and High Energy Physics