Recent results from exclusive processes

An experimental review is given of the processes of diffraction dissociation under the headings; diffraction dissociation reactions, partial wave analysis of a three body system, coherent production on nuclei, main diffraction channels (N→Nπ, N→Nππ, π→πππ, K→Kππ), and rare diffraction channels. Although the picture of diffraction dissociation processes looks complicated a number of regularities have been established namely; all the processes considered here have the cross sections which slowly decrease with energy, the low mass diffractive clusters produced at the ISR energies in both the single and double diffraction dissociation processes carry all the characteristics of the clusters observed at lower energies, dsigma/sub(dt) cross sections for these low mass enchancements show a steep exponential dependence on t up to t approximately 0.4 GeV2, the mesonic diffractive clusters are very complex, the baryonic diffractively produced clusters, similarly to the mesonic ones, have very complex spin composition, both mesonic and baryonic low mass diffractive clusters show little resonance structure and have very small cross sections for the interaction with nucleons, natural parity states Jsup(P) = 2+, A2 and K**(1420) are produced diffractively. (U.K.)