Deuteron Spin Alignment in High-Energy Elastic Proton-Deuteron Backscattering

Abstract

The spin alignment $〈T_{20}〉$ of recoil deuterons in high-energy $p-d$ elastic scattering at 180° is calculated in two models. One is the simple nucleon-transfer or pickup mechanism. The other is the extended pickup mechanism of Kerman and Kisslinger that includes, in addition to nucleon exchange, the exchange of $N^{*}\mathrm{}\left(1688\right)\mathrm{}$ resonance which is taken to be present in the deuteron with a small (1-2%) probability. For proton lab energies around 1 GeV, the Kerman-Kisslinger model gives alignments that are characteristically different from the predictions of the simple exchange model, showing that the presence of the $N^{*}$ in the deuteron has a significant effect at these energies.