ppInteractions at 10 GeV/c

Abstract

About 3700 two-prong and 5600 four-prong events of 10-GeV/c $\mathrm{pp}$ interactions in the Saclay 81-cm hydrogen bubble chamber have been measured and analyzed. The reliability of the identification of the different final states has been checked using Monte Carlo-generated events. For the channels accessible to analysis, cross sections and invariant-mass distributions are given. The c.m. angular distributions and the mean values of the transverse momentum for all final-state particles are shown and discussed. Production of ${\Delta }^{++}\mathrm{}\left(1236\right)\mathrm{}$ accounts for about 30% of the cross section $\sigma (pp\to \mathrm{pn}{\pi }^{+})=4.1\mathrm{}\pm 0.4$ mb. About 50% of the cross section $\sigma (pp\to \mathrm{pp}{\pi }^{+}{\pi }^{-})=2.4\mathrm{}\pm 0.2$ mb can be accounted for by ${\Delta }^{++}$ production. Production of nucleon isobars at 1450, 1520, and 1730 MeV and their subsequent decay into $p{\pi }^{+}{\pi }^{-}$ are investigated. Their cross sections, $t$ dependences, and branching ratios are determined, using a one-pion-exchange model (OPEM) for calculating the background distributions. The production of resonances decaying into $p{\pi }^{-}$ at 1236, 1500, and 1690 MeV is seen, and cross sections are given. Resonance production in the $\mathrm{pp}{\pi }^{+}{\pi }^{-}{\pi }^0$ and $\mathrm{pn}{\pi }^{+}{\pi }^{+}{\pi }^{-}$ reactions is studied using background curves calculated with a model based on simple parametrizations of the c.m. momentum distributions. The production of nucleon isobars accounts for nearly 100% of these reactions. For the reactions $\mathrm{pp}\to \mathrm{pp}\omega , \mathrm{pp}\eta , \mathrm{and} \mathrm{pp}{f}^0$, the cross sections found are 0.16±0.03, 0.16±0.07, and 0.10±0.04 mb, respectively, corrected for unobserved decay modes. It is shown that most of the gross features of the pion-production reactions can be explained by the OPEM with the form factors of Ferrari and Selleri.