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 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 to be very sensitive to the high-density behavior of nuclear symmetry energy. The nuclear radial flow, however, depends only weakly on the symmetry energy.