Normal or abnormal isospin-fractionation as a qualitative probe of   nuclear symmetry energy at supradensities
  Within two different frameworks of isospin-dependent transport model, effect of nuclear symmetry energy at supradensities on the isospin-fractionation (IsoF) was investigated. With positive/negative symmetry potential at supradensities (i.e., values of symmetry energy increase/decrease with density above saturation density), for energetic nucleons, the value of neutron to proton ratio of free nucleons is larger/smaller than that of bound nucleon fragments. Compared with extensively studied quantitative observables of nuclear symmetry energy, the normal or abnormal isospin-fractionation of energetic nucleons can be a qualitative probe of nuclear symmetry energy at supradensities. 
Wen-Mei Guo, Gao-Chan Yong, Yongjia Wang, Qingfeng Li, Hongfei Zhang,   Wei Zuo
nucl-th nucl-ex