The ASY-EOS experiment at GSI: investigating the symmetry energy at   supra-saturation densities
  The elliptic-flow ratio of neutrons with respect to protons in reactions of neutron rich heavy-ions systems at intermediate energies has been proposed as an observable sensitive to the strength of the symmetry term in the nuclear Equation Of State (EOS) at supra-saturation densities. The recent results obtained from the existing FOPI/LAND data for $^{197}$Au+$^{197}$Au collisions at 400 MeV/nucleon in comparison with the UrQMD model allowed a first estimate of the symmetry term of the EOS but suffer from a considerable statistical uncertainty. In order to obtain an improved data set for Au+Au collisions and to extend the study to other systems, a new experiment was carried out at the GSI laboratory by the ASY-EOS collaboration in May 2011. 
P. Russotto, M. Chartier, E. De Filippo, A. Le F\'evre, S. Gannon, I.   Ga\v{s}pari\'c, M. Ki\v{s}, S. Kupny, Y. Leifels, R....
nucl-ex