Longitudinal- and Transverse-Momentum Distributions forπ−Mesons in18.5−GeVc π±pInteractions

Abstract

New data are presented on the longitudinal- and transverse-momentum spectra of ${\pi }^{-}$ mesons produced in both ${\pi }^{-}p$ and ${\pi }^{+}p$ interactions at 18.5 $\frac{\mathrm{GeV}}{c}$. These distributions are studied as a function of the number of charged particles observed in the final states. The spectra are discussed in terms of relevant models and are compared with similar data from $\mathrm{pp}$ interactions. The data cannot be factorized into a simple product of independent functions of longitudinal and transverse momentum. The distributions suggest strongly that a simple quark-quark model is inadequate to explain multipion production.