Symmetry energy dependence of long-timescale isospin transport

Abstract

Isospin transport occurring within dinuclear projectile-like fragments (PLFs) produced in heavy-ion collisions is explored as a probe of the nuclear symmetry energy. Within the framework of the constrained molecular dynamics (CoMD) model, the existence of the long-lived dinuclear PLFs, for up to $800 \mathrm{fm}/c$, is observed. It is demonstrated that changes in the $\ensuremath{\langle}N/Z\ensuremath{\rangle}$ of the two fragments resulting from the breakup of the dinuclear PLF is due to isospin transport. The rate of the transport between the two fragments is shown to be dependent on the slope of the symmetry energy at saturation density. Comparison of the CoMD calculations with experimental data establishes that the evolution of $\ensuremath{\langle}N/Z\ensuremath{\rangle}$ could be used to constrain the density dependence of the symmetry energy.