Symmetry energy extraction from primary fragments in intermediate heavy-ion collisions

An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature, asym/T, for the heavy-ion reactions near the Fermi energy region, based on the modified Fisher Model（MFM）. This method is applied to the primary fragments of the Anti-symmetrized Molecular Dynamics（AMD）simulations for the reactions of^40 Ca ＋^ 40 Ca at 35 Me V/nucleon. The density and the temperature at the fragment formation stage are extracted using a self-consistent method.