InclusiveΔ++production inπ−pinteractions at 147 GeV/c

Abstract

The inclusive production of the ${\Delta }^{++}\mathrm{}\left(1232\right)\mathrm{}$ resonance in ${\pi }^{-}p$ collisions at 147 GeV/c has been studied. The ${\Delta }^{++}$ is found to be produced in comparable amounts in four-, six-, eight-, and ten-prong events. The Feynman-$x$, $t^{\prime }$, ${P_T}^2$, and the decay angular distributions of the ${\Delta }^{++}$ are found to be consistent with the predictions of a one-pion-exchange model with absorption. Essentially all of the ${\Delta }^{++}$ are found to be associated with a ${\Delta }^{++}$ ${\pi }^{-}$ low-mass enhancement. The ${\Delta }^{++}$ cross section is approximately constant from 11 to 205 GeV/c, which could indicate that the ${\Delta }^{++}$ is a decay product of a target-fragmentation object. While the one-pion-exchange character of the ${\Delta }^{++}$ production and the target-fragmentation character of the ${\Delta }^{++}{\pi }^{-}$ low-mass enhancement can both be described in terms of a Deck-type diagram, a Monte Carlo study indicates that any mechanism that produces particles with limited transverse momentum will yield a ${\Delta }^{++}{\pi }^{-}$ low-mass enhancement.