Pi +d--> pi

Abstract

The vector analyzing power, ${\mathrm{iT}}_{11}$, has been measured for the ${\ensuremath{\pi}}^{+}$d\ensuremath{\rightarrow}${\ensuremath{\pi}}^{+}$pn reaction in a kinematically complete experiment. The dependence of ${\mathrm{iT}}_{11}$ on the momentum of the proton has been obtained for 35 pion-proton angle pairs at pion bombarding energies of 180, 228, and 294 MeV. The data are compared with a relativistic Faddeev calculation. The theoretical prediction that there is a single universal shape for ${\mathrm{iT}}_{11}$, which is positive at low proton momenta and negative at large proton momenta, independent of the final pion and proton angles or of the incident pion energy is confirmed by the experiment.