Proton differential elliptic flow and the isospin dependence of the nuclear equation of state - art. no. 054604

Within an isospin-dependent transport model for nuclear reactions involving neutron-rich nuclei, we study the first-order direct transverse flow of pr otons and their second-order differential elliptic flow as a function of tr ansverse momentum. It is found that the differential elliptic flow of midra pidity protons, especially at high transverse momenta, is much more sensiti ve to the isospin dependence of the nuclear equation of state than the dire ct flow. Origins of these different sensitivities and their implications to the experimental determination of the isospin dependence of the nuclear eq uation of state by using neutron-rich heavy-ion collisions at intermediate energies are discussed.