Charged-Particle Multiplicity Distributions In 100-Gev-C Pd And Pi-D Interactions

We present data on and π− n collisions obtained from an exposure of the 30′' FNAL deuterium filled bubble chamber to a mixed beam with a momentum of 100 GeV/c. We find that in 17±2% of the collisions with the antiproton there is an interaction on the spectator while for the collisions with π− mesons the corresponding number is 15±2%. The and π− n multiplicity distributions have average charged multiplicities of 6.46±0.07 and 6.53±0.08 respectively. The average multiplicities for both types of interactions are slightly smaller than those for the corresponding reactions on hydrogen by an amount that is the same as observed at other energies. As an estimate of annihilation we have calculated the difference for each prong numbern. We find an average multiplicity of 9±1, a value close to that for annihilation at the same energy. combining our data with lower energy annihilation data, we observe that the average negative multiplicity is systematically larger than that for annihilation similar to the difference between neutron and proton target data with other beam projectiles.