Quantitative analysis of the relation between entropy and nucleosynthesis in central Ca + Ca and Nb + Nb collisions

The final states of central Ca + Ca and Nb + Nb collisions at 400 and 1050 MeV/nucleon and at 400 and 650 MeV/nucleon, respectively, are studied with two independently developed statistical models, namely the classical microcanonical model and the quantum-statistical grand canonical model. It is shown that these models are in agreement with each other for these systems. Furthermore, it is demonstrated that there is essentially a one-to-one relationship between the observed relative abundances of the light fragments p, d, t, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, and α and the entropy per nucleon, for breakup temperatures greater than 30 MeV. Entropy values of 3.5–4 are deduced from high-multiplicity selected fragment yield data.