Abstract The emission of light particles in coincidence with fast fission in near peripheral reactions of 40Ar+197Au at 30 MeV/u beam energy has been studied by using the Improved Quantum Molecular Dynamics Model (ImQMD). It is demonstrated that in the symmetrical fast fission of the heavy target-like fragment (TLF), the emission of the coalescence-invariant neutrons (CIN) is enhanced particularly at large angles in comparison to that in the events without fission. Due to the enhanced CIN emission and the accumulation of the isospin effect in the long-time process, the yield ratio of the CIN to the coalescence-invariant protons (CIP) in the fission events exhibits significant dependence on the symmetry energy E sym ( ρ ) varying with density. Considering that the large angle neutrons are experimentally advantageous to measure for the lower flying velocity and lower multiplicity, we emphasize that the yield ratio R CINP at large angles in the fast fission events can be used as a novel probe of the nuclear symmetry energy at sub-saturation densities.

中文翻译：

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与快速裂变同时发生的光粒子发射的对称能量效应

摘要 使用改进的量子分子动力学模型 (ImQMD) 研究了 40Ar+197Au 在 30 MeV/u 束能量下的近外围反应中与快速裂变同时发生的光粒子发射。结果表明，在重靶样碎片 (TLF) 的对称快速裂变中，与没有裂变的事件相比，聚结不变中子 (CIN) 的发射特别是在大角度下增强。由于 CIN 发射增强和长时间过程中同位旋效应的积累，裂变事件中 CIN 与聚结不变质子 (CIP) 的产率对对称能 E sym ( ρ ) 随密度变化。