[en] The results are presented of a study of the inclusive reaction p+n→p+X at 19 GeV/c in the target fragmentation region, i.e., at small four momentum transfers from the target neutron to the final state proton. The cross section and inclusive structure function of the neutron fragmentation processes are determined. A comparison with data at higher energies shows that the cross section at fixed t and M²/s is only slightly energy dependent. A satisfactory description of the structure function is obtained for t<1 (GeV/c)² with a triple Regge model with a pion exchange at the pn-vertex and no free parameters. (Z.J.)

[en] Data on the reaction pn→pX are extracted from a pd experiment in the CERN 2m DBC at 19 GeV/c. The cross section for neutron fragmentation events with |t| < 1 (GeV/c)² is determined and compared with data at high energies at fixed Msub(x)²/s and t. We find that the cross section can be described with the triple-Regge formula taking into account only the pion exchange contributions i.e. ππP and ππR terms. A leading particle effect consistent with the pion exchange model is observed in the longitudinal momentum distribution of the negative pions in the final state of reaction pn→pX, when transformed to the rest frame of the recoiling system X. (author)

[en] Data on the reaction pn→pX are extracted from a pd experiment in the CERN 2 m DBC at 19 GeV/c. The cross-section for neutron fragmentation events with /t/<1 (GeV/c)² is determined and compared with data at high energies at fixed M²sub(x)/s and t. It is found that the cross-section can be described with the triple-Regge formula taking into account only the pion exchange contributions, i.e. the ππP and ππR terms. A leading-particle effect consistent with the pion exchange model is observed in the longitudinal-momentum distribution of the negative pions in the final state of the reaction pn→pX, when transformed to the rest frame of the recoiling system X. (author)

[en] The coherent reactions pd→pdπ⁺π^-, pd→pdπ⁺π^-π⁰ and pd→ndπ⁺π^- are studied at 19 GeV/c. In the two first reactions strong production of Δ²⁺(1236) is observed. Some rho and ω production is seen in the second reaction. Production of d*⁰ and d*⁺ is observed in the first and second reactions respectively. Clear enhancements are seen at 1500 and 1700 MeV in the pπ⁺π^- mass spectrum of the pd→pdπ⁺π^- channel. From an analysis of the moments of the decay angular distributions of the pπ⁺π^- system it is found that the most important contributions to the 1450 and 1700 MeV structures come from spin 3/2 and spin 5/2 states respectively. Evidence is found against s-channel helicity conservation and some evidence against t-channel helicity conservation. (Auth.)

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