Omega Production inπ+d→π+π−π0ppat 4.19 GeV/c

We report on ∼340 events of the reaction ${\pi }^{+}n\to {\omega }^{0}p$ at a beam momentum of 4.19 GeV/c. The differential cross section shows neither a broad dip for $t<-0.2\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ nor a dip in the region $t\approx -0.6\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. There is a 2-standard-deviation dip in ${\rho }_{00}$ between $t=-0.2\mathrm{}$ and $t=-0.3\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ and a small negative value of $\mathrm{Re}{\rho }_{10}$ for $t<-1.0\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. The dip in ${\rho }_{00}$ is consistent with the vanishing, in that region of $t$, of an exchanged trajectory with unnatural parity. A simple Regge-model calculation with $\rho +B$ exchange does not reproduce the data.