Charge-Exchange Scattering of Negative Pions at 150 Mev

Abstract

The charge-exchange scattering of negative pions by hydrogen has been measured at a bombarding energy of 150 Mev. The energy distribution of gamma rays from the decay of the neutral pions was measured with a lead glass Čerenkov counter at laboratory angles of 45°, 75°, 105°, and 135°. If the charge exchange differential scattering cross section in the center-of-mass system is expanded as a series of Legendre polynomials, the result is: $\frac{d\sigma }{d\Omega }=(1.00\mathrm{}\pm 0.03)[3.39\pm 0.11-(1.54\pm 0.29\left)P_1\right({cos\theta }^{\prime })+(3.57\mathrm{}\pm 0.56\left)P_2\right({cos\theta }^{\prime }\left)\right]\mathrm{mb}-{\mathrm{sr}}^{-1\mathrm{}}.$ The total cross section for charge exchange, obtained by integration, is then ${\sigma }_{\mathrm{tot}}({\pi }^{-}\to {\pi }^0)=42.6\mathrm{}\pm 1.9$ mb.