Charge-Exchange Scattering of Negative Pions by Hydrogen at 230, 260, 290, 317, and 371 Mev

The differential cross section for charge-exchange scattering of negative pions by hydrogen has been observed at 230, 260, 290, 317, and 371 Mev. The reaction was observed by detecting one gamma ray from the ${\pi }^0$ decay with a scintillation-counter telescope. A least-squares analysis was performed to fit the observations to the function $\frac{d\sigma }{d\omega }=\Sigma \stackrel{5}{l=1\mathrm{}}{a}_l{P}_{l-1\mathrm{}}\left(cos\theta \right)$ in the c.m. frame. The best fit to our experimental measurements requires only $s$- and $p$-wave scattering. The results (in mb) are: The least-squares analysis indicates that $d$-wave scattering is not established in this energy range.