Nuclear symmetry energy and proton-rich reactions at intermediate energies

Abstract

Based on an isospin dependent transport model IBUU, effects of high density behavior of nuclear symmetry energy in the proton-rich reaction ${}^{22}$Si+${}^{22}$Si at a beam energy of 400 MeV/nucleon are studied. It is found that the symmetry energy affects ${\pi }^{+}$ production more than ${\pi }^{-}$. More interestingly, comparing with neutron-rich reactions, for ${\pi }^{-}/{\pi }^{+}$ and dense matter's N/Z ratios, effects of symmetry energy in the proton-rich reaction both show contrary behaviors. The practical experiment by using the proton-rich reaction ${}^{22}$Si+${}^{40}$Ca to study nuclear symmetry energy are also provided.

Comments: 5 pages, 7 figures; title changed and two figures added. PRC, in production