Low-Energy Antiproton Interactions in Hydrogen and Deuterium

The distributions of charged particles resulting from antiproton annihilations in hydrogen and deuterium are compared with the predictions resulting from the "normalized" statistical theory of Fermi. Multiplicities and momentum distributions are shown to be in agreement with the theory if the radius of the interaction volume is chosen to be about 3×${10}^{-13\mathrm{}}$ cm. The values given for the average multiplicities observed in hydrogen and deuterium are 4.94±0.31 and 5.03±0.44, respectively, both somewhat lower than found in the emulsion experiments. $K$-meson production in annihilations was found to be consistent with previous experiments, but the number of events is statistically inadequate to warrant any new conclusions. The total elastic scattering cross sections in hydrogen, though of small statistical significance, are in agreement with recent theoretical calculations.