Study of the reactionp+p→Δ++(1236)+X0at 205 GeV/c

We have studied inclusive ${\Delta }^{++}\mathrm{}\left(1236\right)\mathrm{}$ production for $\left|t_{p\Delta }\right|<\mathrm{}1.0\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ in a 50 000 picture exposure of the 30-inch hydrogen bubble chamber to a 205 GeV/c proton beam. The inclusive ${\Delta }^{++}$ cross section for one hemisphere in the center-of-mass system is (1.30±0.14) mb. The mean charged multiplicity of the system recoiling off the ${\Delta }^{++}$ is in agreement with that for laboratory ${\pi }^{-}p$ interactions at the same energy in the center-of-mass frame. The inclusive ${\Delta }^{++}$ production is compared to inclusive ${\Lambda }^0$ and proton production in the same experiment. The connection between ${\Delta }^{++}$ production and diffraction is discussed. We find that not all ${\Delta }^{++}$ come from the decay of a diffractively-produced state. The $P_T^2$ distribution for the ${\Delta }^{++}$ has a slope of (10.5±0.9) ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{-2\mathrm{}}$ for $P_T^2\lesssim 0.2$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. This slope, together with the decay angular distribution of the ${\Delta }^{++}$ at small momentum transfer, suggests a strong pion-exchange contribution to the inclusive process. We compare the data to the expectation of a triple-Regge model with $\rho$- and $\pi$-exchange contributions.