Interactions of 1.61-BeV/c Antiprotons in Hydrogen Involving Two Outgoing Charged Particles

Interactions of 1.61-BeV/c antiprotons in hydrogen yielding two charged particles have been studied, with particular attention to elastic scattering, single-pion production, and annihilation into three or more pions. Effects of misinterpretation of events are estimated by Monte Carlo calculations. Nine partial cross sections have been measured. The elastic-scattering data show a secondary diffraction peak at about 82° in the center-of-mass system. Single pion production is found to be consistent with charge-conjugation invariance. In the single pion events ($\overline{p}+p\to \overline{N}+N+\pi$) the predominance of low-momentum transfer exceeds that predicted by the single pion exchange formula of Chew and Low. No two-pion resonances have been observed anywhere in the data.