A numerical technique for simulating Ostwald ripening in closed systems and heterogeneous nucleation and growth in open systems is developed. The method is a numerical integration of the quasi-hydrodynamical equation governing the cluster-size distribution using realistic growth rates and conservation conditions. For closed systems, Chakraverty's analytical predictions have been confirmed. For the treatment of open systems, a hybrid representation has been used. This retains classical growth rates for large clusters but substitutes atomistic expressions for small ones. It was possible to simulate nucleation and growth up until coalescences become important and a new insight into the dynamics of the process has been gained.

Ratios of the invariant distributions of produced particles, R(π+/π−), R(p̄/π−), R(K−/π−) and R(K+/p), have been calculated in the diffractive excitation model. Two free parameters are used to adjust the relative normalization. The shapes of the ratios as functions of x are essentially independent of any arbitrary parameters. The results agree with the data very well.