Nuclear symmetry energy and proton-rich reactions at intermediate energies

TL;DR

This paper investigates how the high-density behavior of nuclear symmetry energy influences pion production and N/Z ratios in proton-rich reactions at intermediate energies using an isospin-dependent transport model.

Contribution

It introduces a study of symmetry energy effects in proton-rich reactions, highlighting contrasting behaviors compared to neutron-rich reactions and proposing practical experimental approaches.

Findings

Symmetry energy significantly affects $^{+}$ production.

Contrasting effects observed in $^{-}/^{+}$ ratios between proton-rich and neutron-rich reactions.

Proposed experiments using $^{22}$Si+$^{40}$Ca to explore nuclear symmetry energy.

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.