Nucleon effective mass splitting and density-dependent symmetry energy effects on elliptic flow in heavy ion collisions at E_(lab)= 0.09 ~ 1.5 GeV/nucleon
Nucleon effective mass splitting and density-dependent symmetry energy effects on elliptic flow in heavy ion collisions at E_(lab)= 0.09 ~ 1.5 GeV/nucleon
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E_(lab)= 0.09 ~ 1.5 GeV/核子重离子碰撞中核子有效质量分裂和密度相关对称能量对椭圆流的影响
DOI：
10.1088/1674-1137/44/7/074103
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发表时间：
2020
影响因子：
3.6
通讯作者：
Liu Fanxin
中科院分区：
文献类型：
--
作者：
Tong Luyao;Li Pengcheng;Li Fupeng;Wang Yongjia;Li Qingfeng;Liu Fanxin
通过在极端相对论量子分子动力学(UrQMD)模型中结合动量依赖势的同位旋依赖形式，我们系统地研究了中子-质子有效质量分裂m*n-p=m*n-m*p/m和密度相关的核对称能E_(Sym)(ρ)对束流能量从0.09到1.5GeV/核子的~(197)Au+~(197)Au碰撞中椭圆流v_2的影响。结果表明，在较高的束流能量(≥为0.25GeV核子)和两个不同的E_(Sym)(ρ)斜率相差约75 MeV的情况下，当同位旋不对称性δ=(ρ_n-ρ_p)/ρ=0.2时，在饱和密度下m*n-p的变化范围为-0.03~0.03，E_(Sym)(ρ)对中子与质子的v_2差，即v_2~n-v_2~p的影响比m*n-p更大。同时，在较低的束流能量(≤0.25GeV核子)下，V_2~n-V_2~p对E_(Sym)(ρ)和m*_(n-p)都很敏感，而且m*_(n-p)对v_2~n-v_2~p的影响在采用软对称能而不是刚性对称能时随本研究参数的变化更为明显。
By incorporating an isospin-dependent form of the momentum-dependent potential in the ultra-relativistic quantum molecular dynamics (UrQMD) model,we systematically investigate effects of the neutron-proton effective mass splitting m*_(n-p)=m*_n-m*_p/m and the density-dependent nuclear symmetry energy E_(sym)(ρ) on the elliptic flow v_2 in ~(197)Au+~(197)Au collisions at beam energies from 0.09 to 1.5 GeV/nucleon.It is found that at higher beam energies (≥ 0.25 GeV nucleon) with the approximately 75 MeV difference in slopes of the two different E_(sym)(ρ),and the variation of m*_(n-p) ranging from-0.03 to 0.03 at saturation density with isospin asymmetry δ=(ρ_n-ρ_p)/ρ=0.2,the E_(sym)(ρ) has a stronger influence on the difference in v_2 between neutrons and protons,i.e.,v_2~n-v_2~p,than m*_(n-p) has.Meanwhile,at lower beam energies (≤0.25 GeV nucleon),v_2~n-v_2~p is sensitive to both the E_(sym)(ρ) and the m*_(n-p).Moreover,the influence of m*_(n-p) on v_2~n-v_2~p is more evident with the parameters of this study when using the soft,rather than stiff,symmetry energy.