Single-Particle Distributions of $\pi$ Mesons Produced in ${\pi }^{+}p$, $K^{+}p$, $\mathrm{pp}$, and ${\pi }^{-}p$ Collisions at High Energies

A comparison is made of single-particle momentum distributions of pions produced in $7.0-\frac{\mathrm{GeV}}{c} {\pi }^{+}p$, $12.7-\frac{\mathrm{GeV}}{c} K^{+}p$, $28.5-\frac{\mathrm{GeV}}{c} \mathrm{pp}$, and $24.8-\frac{\mathrm{GeV}}{c} {\pi }^{-}p$ interactions. We observe that the distributions for negative pions which have low laboratory momentum (target fragments) in ${\pi }^{+}p$, $K^{+}p$, and $\mathrm{pp}$ interactions agree with each other when normalized by their respective asymptotic total cross sections. However, the corresponding distributions from the ${\pi }^{-}p$ reaction are significantly different from the rest. This difference is particularly interesting in view of recent theoretical predictions for inclusive reactions.