On the determination of the nuclear matter equation of state from pion yield data

Attempts to derive the nuclear matter equation of state from pion yield data have shown that the data can be reproduced by quite different parametrisations of the equation of state. We investigate this ambiguity within the one-dimensional shock wave model by deriving equations of state not restricted to a predefined functional form. The results show that while in principle the dependence of the pion yields on energy can be reproduced by widely differing equations of state, some of these equations of state do not allow for sufficiently high bombarding energies. Others may violate causality inside the experimentally studied energy range, so that the admissible range of equations of state may be narrowed down considerably. Suggestions for further improvement are made. (orig.)