Lifetimes of well characterized hot nuclei via small-angle particle-particle correlations: Ar40+Ag (E/A=7.8 and 17 MeV)

Particle-particle correlations are studied for large- and small-angle separations for the reactions 312 and 680 MeV Ar40+natAg. The spectral shapes and angular ansiotropies allow a characterization of the effective temperatures and spin zones of the hot nuclear emission sources. Small-angle correlations are compared to reaction simulations that employ various parametrizations for the emission time scales. We conclude that the initial lifetime scale for H1,2,3 particle evaporation is of the order of 10-22 s. These times are so short as to suggest a breakdown of the concept of "sequential evaporation," for which a new ansatz is explored.