Reactionp+p→π++dwith Polarized Protons

The reaction $p+p\to {\pi }^{+}+d$ is analyzed. Using the statistical operator methods, we derive: (i) the production cross section for $s$-, $p$-, and $d$-wave mesons for the case of a polarized proton beam; (ii) the polarization of the deuteron for both polarized and unpolarized incident protons. With the restriction to $s$- and $p$-waves, the deuteron polarization gives new information about the production amplitudes; for an unpolarized proton beam for the $p$-wave production only, for a polarized one for $s$-waves as well. We discuss: (i) the possibilities of measuring the deuteron polarization; (ii) the relation of the phases of the production amplitudes to the $\mathrm{pp}$-scattering phases.