EMISSION OF FAST POSITRONS IN INTERMEDIATE-ENERGY ION-ION COLLISIONS

The differential cross section for the emission of fast positrons in i ntermediate-energy heavy-ion collisions is obtained. Electron-positron pairs produced in the field of a dynamical dinuclear system are assum ed to be the main source of positrons. Nucleus-nucleus interaction is taken into account in the quantum optical model, which was formerly us ed to describe the emission of pions and high-energy photons. It is sh own that the spectral and angular distributions of positrons contain i nformation about the reaction mechanism and about the properties of nu cleus-nucleus interaction.