Use of inelastic pion scattering to study isospin mixing in nuclei.

Abstract

Nuclear structure effects are shown to play a significant role in determining the pion asymmetries expected for the excitation of isospin mixed states. As an example, the ${\ensuremath{\pi}}^{+}$/${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$ ratio for excitation of the giant dipole resonance region in $^{4}\mathrm{He}$ is calculated. It is shown that, at the peak of the angular distribution (${\ensuremath{\theta}}_{\mathrm{lab}=30}$\ifmmode^\circ\else\textdegree\fi{}), no significant deviation from unity is expected for the pion ratio if the isospin mixing is at the level of 5%.