Off-shell effects in nucleon-deuteron polarization observables

A separable representation of the S-wave Paris potential and a phase-shift equivalent Yamaguchi-type potential significantly differing in their off-shell behaviours are used to calculate second-order polarization observables of elastic nucleon-deuteron scattering at Esub(D)=10 and 20 MeV. Off-shell effects are found that stem from differences in the nuclear interaction in the inner region r< or approx.1.2 fm. Adding approximate Coulomb-distortion contributions to the purely nuclear Faddeev amplitudes proton-deuteron predictions are obtained. Coulomb effects are not found to be negligible. Comparison with experimental data, in particular, the spin-correlation parameter Csub(y,y) of the reaction 1H(d, d)1H for Esub(D)=10 MeV vector-polarized deuterons and the spin-transfer coefficients Ksub(y)sup(y), Ksub(x)sup(x) and Ksub(z)sup(x) for 2H(p, p)2H at Esub(p)=10 MeV, prefer the interaction model that contains an intermediate-range repulsion. (orig.)