Analysis of the charge-exchange reaction pp → (pπ+)(pπ-) and of Δ++Δ0 production at the CERN TSR

Results are presented of a systematic analysis of charge-exchange double dissociation in proton-proton collisions at the CERN Intersecting Storage Rings. The data, obtained with the Split-Field Magnet detector, cover the entire ISR energy range between √s = 23 GeV and √s = 63 GeV at five standard energies. Double resonance production is observed in the Δ++Δ- and Δ++N0(1688) final states. The mass spectra of the pπ- system show more pronounced resonant signals in the backward Jackson hemisphere. A detailed analysis of differential cross sections shows a forward peak typical of absorbed pion exchange decreasing as ssup(-1.81 +- 0.06), folowed by a much gentler exponential behaviour associated with a trajectory typical of rho-A2 exchange. The high-energy transition to this regime is also indicated by a dramatic change in the s-dependence of total cross sections as compared with low-energy data. (Auth.)