THE IMAGINARY PART OF THE NUCLEON SELF-ENERGY IN HOT NUCLEAR-MATTER

A semiphenomenological approach to the nucleon self-energy in nuclear matter at finite temperatures is followed. It combines elements of the rmo field dynamics for the treatment of finite temperature with a mode l for the self-energy, which evaluates the second-order diagrams takin g the needed dynamics of the NN interaction from experiment. The appro ach proved to be accurate at zero temperature to reproduce Im Sigma an d other properties of nucleons in matter. In the present case we apply it to determine Im Sigma at finite temperatures. An effective NN cros s section is deduced, which can be easily used in analyses of heavy-io n reactions.