Production of Neutral Mesons by 340-Mev Protons on Hydrogen

The production of neutral mesons by 340-Mev protons on hydrogen has been measured directly by detecting a single gamma ray from the two gamma-ray decay of a neutral meson, at 90° to the proton beam. A liquid hydrogen target and a focusing Čerenkov counter are described. The ratio of the cross section for neutral meson production from hydrogen relative to carbon is $\frac{{\sigma }_{\mathrm{H}}}{{\sigma }_{\mathrm{C}}}=0.0059\mathrm{}\pm 0.0009,$ where the error is standard deviation. Using the absolute cross section of neutral meson production from carbon as 1.5×${10}^{-27\mathrm{}}$ ${\mathrm{cm}}^2$, one obtains the neutral meson production cross section for hydrogen to be 8.8×${10}^{-30\mathrm{}}$ ${\mathrm{cm}}^2$.