Interaction of Positive Pions with Hydrogen at 600 MeV

Abstract

The Berkeley 15-in. hydrogen bubble chamber was used to investigate ${\pi }^{+}-p$ interactions at 600 MeV. There were 1738 good events, of which 71.9±0.8% were elastic. Partial waves up to at least $D_{\frac{5}{2}}$ are required to fit the elastic angular distribution. The inelastic events were almost entirely single-pion production. The ratio $\frac{\mathrm{}(p+0\mathrm{})\mathrm{}}{\mathrm{}(n++)\mathrm{}}$ was found to be 5.5±0.8 which agrees well with 4.9 predicted by the ($\frac{3}{2}, \frac{3}{2}$) pion-nucleon isobar model of Olsson and Yodh. It is also consistent with 6.5 predicted by Sternheimer and Lindenbaum. The pion momentum spectra and the $\pi -\pi$ Q-value distributions also support the Olsson and Yodh model. Thus the ($\frac{3}{2}, \frac{3}{2}$) pion-nucleon isobar is apparently the principal mechanism for single-pion production at 600 MeV. Angular distributions for the single-pion-production data are presented.