Interpretation of Fission-Fragment Angular Distributions in Heavy-Ion Fusion Reactions

Fission-fragment angular distributions in a number of heavy-ion-induced fusion reactions are explained on the basis that for composite systems with fission barrier heights comparable to their intrinsic temperatures, a fraction of the fission events take place before the fused system equilibrates fully in the K degree of freedom. A value of about 8×{}10^-21 s is deduced for the characteristic time for K equilibration.