Momentum dependence of the symmetry potential and nuclear reactions induced by neutron-rich nuclei at RIA

Effects of the momentum dependence of the symmetry potential in nuclear reactions induced by neutron-rich nuclei at Rare Isotope Accelerator (RIA) energies are studied using an isospin- and momentum-dependent transport model. It is found that symmetry potentials with and without the momentum-dependence but corresponding to the same density-dependent symmetry energy $E_{sym}\left(\rho \right)$ lead to significantly different predictions on several $E_{sym}\left(\rho \right)$-sensitive experimental observables. The momentum dependence of the symmetry potential is thus critically important for investigating accurately the equation of state and novel properties of dense neutron-rich matter at RIA.

Figure 1

(Color online) The density dependence of the potential and kinetic parts of nuclear symmetry energy.

Figure 2

(Color online) Strengths of the symmetry potentials with and without (solid) the momentum-dependence as a function of density as measured by the difference between neutron and proton potentials.

Figure 3

(Color online) Isospin asymmetry (upper window) and neutron-proton differential flow (lower window) of free nucleons as a function of rapidity. The solid (dashed) lines are calculated with the momentum-independent(-dependent) symmetry potential.

Figure 4

(Color online) The ratio of free neutron to proton multiplicity as a function of transverse momentum at midrapidity. The solid (dashed) line is calculated with the momentum-independent (-dependent) symmetry potential.