Average Charged Multiplicity inπ−+p→πfast−+Xat 147 GeV/cand Comparison with Other Reactions

The average charged multiplicity, $〈n_x〉$, has been determined for ${\pi }^{-}+p\to \pi _{\mathrm{fast}}^{}{}_{}{}^{-}+X$ at 147 GeV/c and is found to increase linearly with $\mathrm{}\left|t\right|\mathrm{}$ as well as $\ln M_x^{}{}_{}{}^2$. The coefficient of the $\ln M_x^{}{}_{}{}^2$ term is approximately equal to that for other reactions, but the absolute value of $〈n_x〉$ is significantly smaller even when it is analyzed in terms of the energy available. This result is discussed in the framework of a simple model.