The
ASY-EOS experiment at GSI:
investigating symmetry energy at supra-saturation densities,
P. Russotto, INFN-LNS & Università di Catania, Italy
− The elliptic-flow
ratio of neutrons with respect to protons or light complex
particles in
reactions of neutron rich heavy-ions at intermediate energies is
proposed as an
observable sensitive to the strength of the symmetry term in the
nuclear
equation of state at supra-saturation densities. The results obtained from the
existing
FOPI/LAND data for 197Au+197Au collisions
at 400
MeV/nucleon in comparison with the UrQMD model favours a
moderately soft
symmetry term but suffer from a considerable statistical
uncertainty [1]. 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. The
flows of neutrons, protons and light
complex particles were measured for 197Au+197Au,
96Ru+96Ru,
and 96Zr+96Zr collisions at 400
MeV/nucleon using the
LAND neutron detector, the forward part of CHIMERA device, the
Aladin ToF-Wall,
the Si-CsI Krakow Array and the Microball detector. First results will be
reported.