Isospin dependence of nucleon emission and radial flow in heavy-ion   collisions induced by high energy radioactive beams
  Using an isospin- and momentum-dependent transport model we study the emission of free nucleons and the nuclear radial flow in central heavy-ion collisions induced by high energy radioactive beams. The midrapidity neutron/proton ratio and its transverse momentum dependence are found very sensitive to the high density behavior of nuclear symmetry energy. The nuclear radial flow, however, depends only weakly on the symmetry energy. 
Bao-An Li, Gao-Chan Yong and Wei Zuo