Recoil Protons from Meson Photoproduction in Hydrogen and Deuterium

The spectrum of photoprotons produced by 500-Mev bremsstrahlung on hydrogen and deuterium has been measured at laboratory angles of 29.7°, 41.2°, and 51.8° with a telescope of three scintillation counters. From the hydrogen data the ${\pi }^0$ cross section of hydrogen was obtained, which agrees with the previous results of this laboratory. The contribution of the deuterium photodisintegration reaction was subtracted from the deuterium counting rate and the deuterium-to-hydrogen ratio of recoil protons from meson photoproduction was obtained. This ratio was also calculated from the deuterium ${\pi }^{-}$ and hydrogen ${\pi }^0$ photoproduction cross sections, by means of the "spectator model" of the deuteron. In this model photons interact with only one of the deuterium nucleons and the initial momentum of the target nucleon is taken into account. The ratio predicted by this model is significantly larger than the experimental ratio.