Extracting information on the nuclear equation of state from K production in heavy ion collisions

In [1] we studied the question if decisive information on the nuclear EOS can be extracted from subthreshold kaon production in heavy ion collisions. The KaoS Collaboration has performed systematic measurements of the K production far below threshold in heavy (Au+Au) and light (C+C) systems [2]. Looking at the ratio R built from heavy and light systems possible uncertainties which might still exist in the theoretical calculations should cancel out to a large extent which allows to draw reliable conclusions. Furthermore, far below threshold the kaon production is a highly collective process and a particular sensitivity to the compression of the participant matter is expected. In [1] we calculated this excitation function for a soft/hard EOS including the in-medium kaon potential shown in Fig. 1. The comparision to the KaoS data [2] strongly favours a soft EOS. To base this conclusion on even more model