Evidence for a Novel Spin Dependence in the Nucleus-Nucleus Interaction

It is demonstrated that in polarized heavy-ion scattering the effects of a second-rank spin-dependent interaction depending quadratically on momentum ($T_P$-type) can be clearly distinguished from the more usual $T_R$-type tensor interaction which depends quadratically on position. A simple criterion involving the ratio of two components of the tensor analyzing power for elastic scattering is proposed, and it is shown that the existing data for ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ scattering from ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ offer the first evidence for a $T_P$-type interaction in nuclear physics.