Inelastic diffraction and color-singlet gluon clusters in high-energy hadron-hadron and lepton-hadron collisions

It is proposed that the "colorless" objects which manifest themselves in la rge-rapidity-gap events are color-singlet gluon clusters due to self-organi zed criticality (SOC), and that optical-geometrical concepts and methods ar e useful in examining the space-time properties of such objects. A simple a nalytical expression for the t dependence of the inelastic single diffracti ve cross section d sigma/dt (t is the four-momentum transfer squared) is de rived. Comparison with existing data and predictions for future experiments are presented. The main differences and similarities between the SOC appro ach and the "partons in the Pomeron (Pomeron and Reggeon)" approach are dis cussed.