Statistical interpretation of joint multiplicity distributions of neutrons and charged - particles

Experimental joint multiplicity distributions of neutrons and charged particles provide a striking signal of the characteristic decay processes of nuclear systems following energetic nuclear reactions. They present, therefore, a new tool for testing theoretical models for such decay processes. The power of this experimental tool is demonstrated via a comparison of an experimental joint multiplicity distribution to the predictions of three different theoretical models of nuclear multi-fragmentation propagated in the current literature. Two of these models are shown to fail this test decisively. For example, the direct evidence for a non-linear correlation between average transverse energy (E t) of charged products and average excitation energy (E *), provided by multiplicity distributions, is shown to challenge statistical interpretations of nuclear pseudo-Arrhenius plots. This feature provides also an unambiguous distinction between Copenhagen and Berlin models of nuclear multi-fragmentation.