The ASY-EOS experiment at GSI: investigating the symmetry energy at supra-saturation densities

Abstract

The elliptic-flow ratio of neutrons with respect to protons in reactions of\nneutron rich heavy-ions systems at intermediate energies has been proposed as\nan observable sensitive to the strength of the symmetry term in the nuclear\nEquation Of State (EOS) at supra-saturation densities. The recent results\nobtained from the existing FOPI/LAND data for $^{197}$Au+$^{197}$Au collisions\nat 400 MeV/nucleon in comparison with the UrQMD model allowed a first estimate\nof the symmetry term of the EOS but suffer from a considerable statistical\nuncertainty. In order to obtain an improved data set for Au+Au collisions and\nto extend the study to other systems, a new experiment was carried out at the\nGSI laboratory by the ASY-EOS collaboration in May 2011.\n