Constraining the density dependence of the symmetry energy in the nuclear equation of state using heavy ion beams

The density dependence of the symmetry energy in the equation of state of asymmetric nuclear matter (N/Z > 1) is important for understanding the structure of systems as diverse as the atomic nuclei and neutron stars. Due to a lack of understanding of the basic nucleon-nucleon interaction for matter that is highly asymmetric and at non-normal nuclear density, this very important quantity has remained largely unconstrained. Recent studies using beams from the Cyclotron Institute of Texas A&M University constrain the density dependence of the symmetry energy. A dependence of the form E(sym)(rho) = C(rho/rho(0))(gamma), where C = 31.6 MeV and gamma = 0.69, is obtained. Their implications to both astrophysical and nuclear physics studies are discussed. (c) 2007 Elsevier B.V. All rights reserved.