第十四届全国核结构大会 利用不同出射粒子的平衡能量探测对称能密度依赖 报告人：王永佳 指导老师：李庆峰 湖州师范学院 2012.04 浙江 湖州
1 2 3 4 5 UrQMD transport model Nuclear symmetry energy Balance energy---depends on particle species Isospin dependence of balance energy Results Summary & Conclusion Outline
Nuclear symmetry energy It is important in both nuclear physics and astrophysics. It is not well constrained right now. Super soft IBUU04: Z. Xiao et al. PRL102.062502 Moderately soft UrQMD: P.Russotto et al. PLB697.471 Super stiff LQMD: Zhao-Qing Feng Gen-Ming Jin PLB683.140
Why we study Balance energy? 70-80A MeV 50-60A MeV • Detector acceptance and reaction plane dispersion affect balance energy weakly. [Ref.] Deniel Joseph Magestro Ph.D Thesis (MSU 2000) • Balance energy depends on particle species, or not? • Old Experiment: not highly depends on particle species • Recent Experiment: depends on particle species [Ref.] EPJA 30. 31-46
Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model • Soft-EoS with momentum dependence K=200MeV • Density and momentum dependent NN elastic cross section [Ref.] Qingfeng Li et al. PRC83.044617
Calculations More than 500, 000 events for each case were calculated. [Ref.] Chenchen Guo et al. Sci China- Phys G: Mech Astron 55(2) 252-259
N/Z mass N/Z mass N/Z mass The inital N/Z and particle species dependent balance energy i. Balance energy increases with increasing N/Z. ii. Balance energy decreases with increasing mass.
The influence of symmetry potential on balance energy of free neutrons is strongest of all.
Summary & Conculsion • Balance energy of light particles emitted from mass symmetric HICs with isotopes, isobars and isotones has been studied. • The balance energy of free neutrons is sensitive to symmetry energy. • The balance energy of free neutrons from mass symmetric HICs with isotopes can be taken as a sensitive probe to complementary constrain symmetry energy.