Nucleon fragmentation into baryons in proton-nucleon interactions at 19 GeV/c compared with some quark-parton model predictions

We present some new data on baryon production in pn interactions at 19 G-eV/c obtained in a bubble chamber experiment. We determine the longitudinal-momentum spectradσ/dx of the baryon in the reactions pn → pF+X, pn→ pB+X, pn →ΔF++(1232) + X and pn → → ΔB++(1232) + X, where F(B) labels the forward (backward) cm. hemisphere. The spectra of pf and pb are also given when the effects of diffraction and Δ++(1232) resonance production are subtracted. These data, together with dσ/dx of pp→Λ0+X at the same beam momentum, are compared with the predictions of some quark-parton models. Particle multiplicities of nucleons, Δ++(1232) and hyperons are found to be incompatible with the probabilistic quark model of Van Hove.