Differential Cross Sections forpp→pnπ+near Threshold

Differential cross sections from kinematically complete measurements of $\mathrm{pp}\to \mathrm{pn}{\pi }^{+}$ production are presented for proton beam energies of 294.2, 299.5, and 319.5 MeV. Total cross sections are given for 294.2, 299.5, 306.5, 314.3, and 319.5 MeV. The two angular distributions close to threshold are dominated by $s$ wave contributions. Total cross sections within the first 30 MeV of threshold show qualitative agreement with an early theoretical prediction based on PCAC.