Differential cross sections and spin observables $A_y,$ ${\mathrm{iT}}_{11},$ $T_{20},$ and $T_{22}$ are calculated for the $p{d}^3\mathrm{H}{\pi }^{+}$ reaction in a $p\overrightarrow{p}d{\pi }^{+}\hspace{0.5em}$ model at energies near threshold. The results are compared with experimental data for the reactions $\overrightarrow{p}{d}^3\mathrm{He}{\pi }^0$ and $\overrightarrow{d}{p}^3\mathrm{He}{\pi }^0.$ Good agreement of these predictions with the data for the proton analyzing powers is obtained, and for most of the other observables satisfactory agreement is found. Effects of various assumptions in the model are investigated and discussed.

• Received 27 September 1999

DOI:https://doi.org/10.1103/PhysRevC.61.034005