ABSTRACT
This is the first of two chapters devoted to current statistical theories of the multifragmentation decay mechanism.
At excitation energies above about 4 MeV/nucleon an excited nucleus decays by disintegrating into a number of complex fragments and light particles. If most of the complex fragments are produced simultaneously, this process is referred to as prompt multifragmentation or, following our convention, simply multifragmentation. The primary complex fragments may of course be excited and decay on a much longer timescale by evaporation of light particles or even complex fragments. Multifragmentation thus contrasts strongly with evaporation which, via a (presumed) succession of states of temporal equililibrium, produces several light particles together with a more massive evaporation residue. The contrast with the sequential binary decay mechanism is less marked since this latter mechanism may also lead to events containing several complex fragments.
