SOFT BINARY-PROCESSES AND THE PHENOMENOLOGY OF CONFINEMENT

A three-stage model of the charge-exchange reactions pi(-)p --> flux t ube --> pi(0)n is considered. The first stage (pi(-)p --> flux tube) i s the formation of a flux tube by the annihilation of a mesonic (u) ov er bar quark and a protonic u quark at low relative rapidity. The seco nd stage is the stretching of the flux tube, with the d and ud spectat ors placed at its ends, with the relative rapidity ins. The third stag e is the rupture of the flux tube (flux tube --> pi(0)n), resulting in the production of a d (d) over bar pair with low relative rapidity, f ollowed by the evolution of the flux tube fragments into a physical pi (0)n system. The analysis of experimental data in this model leads to the following conclusions: (1) in the spin-flip amplitude, the annihil ation (production) of quarks occurs predominantly in the P-3(0) state; (2) the annihilation probability in this state is close to unity, so that the annihilating quarks can be called ''black''; (3) in the non-s pin-flip amplitude, the P-3(0) mode interferes destructively with othe r annihilation modes (e.g., S-1(0)); (4) the parameters of quark annih ilation prove to be identical in the reactions pi(-)p --> pi(0)n and p i(-)p --> eta n, while the observables of these reactions (i.e., cross sections, the ratio of the spin-flip amplitude to the non-spin-flip a mplitude, etc.), from which the quark-annihilation parameters are dedu ced, differ strongly in magnitude. The quark-annihilation parameters f or charge-exchange reactions are compared with the corresponding quant ities for the production of ordinary resonances in the Isgur-Kokoski m odel.