Effects of symmetry energy in $^{132}\rm {Sn}+^{124}\rm {Sn}$ reaction at 300 MeV/nucleon

Understand

Based on the recently updated Isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we studied the effects of symmetry energy on the neutron to proton n/p ratio and the $\pi^{-}/\pi^{+}$ ratio in central $^{132}\rm {Sn}+^{124}\rm {Sn}$ reaction at 300 MeV/nucleon.

• It is found that the n/p ratio and the $\pi^{-}/\pi^{+}$ ratio in central $^{132}\rm {Sn}+^{124}\rm {Sn}$ reaction at 300 MeV/nucleon mainly probe the symmetry energy in the density region 1-1.5 times saturation density.
• However, the $\pi^{-}/\pi^{+}$ ratio may be able to probe the density-dependent symmetry energy above 1.5 times saturation density by making some kinematic restrictions such as the azimuthal angle and kinetic energy cuts of emitting pions.