Speaker
Description
The Symmetry Energy is a fundamental ingredient of the nuclear matter Equation Of State.
The elliptic-flow ratio of neutrons with respect to protons or light complex particles in
reactions of heavy-ions at pre-relativistic energies has been proposed as an observable sensitive to the strength of the Symmetry Energy at supra-saturation densities.
The results obtained from the existing FOPI/LAND data for Au+Au collisions at 400
MeV/nucleon in comparison with the UrQMD model indicate a moderately soft symmetry energy
but suffer from a considerable statistical uncertainty [1]; these results were confirmed by an independent analysis based on Tubingen QMD [2].
A new experiment, carried out at the GSI laboratory by the ASY-EOS collaboration [3], has given a more stringent constraint for the nuclear symmetry energy at supra-saturation densities.
Moreover, future plans for extending these studies at higher densities, also by using Radioactive Ion Beams, will be discussed.
Talk presented on behalf of the AYS-EOS and NewCHIM collaborations
[1] P. Russotto et al., Phys. Lett. B 697 (2011) 471.`
[2] M.D. Cozma, Phys. Lett. B 700, 139 (2011); M.D. Cozma et al., Phys. Rev. C 88, 044912
(2013).
[3] P. Russotto et al., Eur. Phy. J A 50, 38 (2014); P. Russotto et al., submitted to Phys. Rev. C (2016).
