Asymmetries and cross sections for the reactionp→+p→p+π++nat 800 MeV

Kinematically complete data (analyzing powers and polarized cross sections) for the reaction $\overrightarrow{p}+p\to p+{\pi }^{+}+n$ at 800 MeV have been accumulated at twelve angle pairs with polarized beam and unpolarized target. Analyzing powers as large as 0.6 are observed in the regions of phase space where the ${\Delta }^{++}$ resonant state can be produced. The four-momentum transfer to the proton-pion ${\Delta }^{++}$ resonance varied between 0.09 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ to 0.81 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. Current theories are not capable of reproducing these results in detail.