Implications of spin-current couplings forP±Ain inelastic proton scattering

Nonlocal spin-dependent couplings in the effective nucleon-nucleon interaction are shown to probe current $\otimes$ spin correlations in inelastic nuclear excitations. Together, these couplings and correlations provide an important dynamical source of polarization-analyzing-power differences observed in inelastic proton scattering. This is illustrated explicitly by schematic calculations for $0^{+}\to 1^{+}$ and $0^{+}\to 0^{-}$ transitions. More realistic distorted-wave impulse approximation calculations have been made for the $0^{+}\to 1^{+}$ transition in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ at $E_x=8.9\mathrm{}$ MeV which support the more transparent schematic considerations. Distorted-wave impulse approximation calculations are also compared with experimental (p,p') data for the two lowest $1^{+}$ excitations in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. For isovector $0^{+}\to 1^{+}$ transitions these nuclear structure spin $\otimes$ current correlations also enter $\beta$ decay through the "induced tensor" couplings, and this relationship is used to help identify the nonlocality in the nucleon-nucleon effective interaction.