Charged-particle multiplicity distributions inpdandpninteractions at 400 GeV/c

Charged-particle multiplicity distributions in 400-GeV/c $\mathrm{pd}$ interactions have been studied in an experiment in the Fermilab 30-inch bubble chamber. From the fractions of odd-prong and backward-proton events, a rescatter fraction of 0.22±0.01 is found (for $N\ge 3$). The $\mathrm{pn}$ multiplicity distribution is obtained from the odd-prong distribution plus a no-cascade assumption. After making one-prong and two-prong estimates, mean charged-particle multiplicities of 9.49±0.12 for $\mathrm{pd}$ (including slow particles) and 8.57±0.12 for $\mathrm{pn}$ are obtained. In the incident momentum range 100 to 400 GeV/c, $\mathrm{pd}$ and $\mathrm{pp}$ distributions are very similar to each other and are different from $\mathrm{pn}$ distributions.