π-Meson Production in 2.9-BeVp−pCollisions

Detailed measurements of the production of charged $\pi$ mesons in proton-proton collisions are reported. The observed results are compared with the "isobar" and "one-pion exchange" models and for single production are in agreement if only the "resonant" part of the $\pi -p$ cross section is used and if the angular distribution ${cos}^{16}\theta$ is introduced for the production of the ${N_1}^{*}$ isobar. The effects of higher resonances are also considered.