By incorporating an iso spin-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 ma...By incorporating an iso spin-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 Esym(ρ)on the elliptic flow v2 in197Au+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 Esym(ρ),and the variation of m*n-p ranging from-0.03 to 0.03 at saturation density with isospin asymmetryδ=(ρn-ρp)/ρ-0.2,the Esym(ρ)has a stronger influence on the difference in v2 between neutrons and protons,i.e.,v2n-v2p,than m*n-p has.Meanwhile,at lower beam energies(≤0.25 GeV/nucleon),v2n-v2p is sensitive to both the Esym(ρ)and the m*n-p.Moreover,the influence of m*n-p on v2n-v2p is more evident with the parameters of this study when using the soft,rather than stiff,symmetry energy.展开更多
基金Supported in part by the National Natural Science Foundation of China(11875125,11947410,11847315,11505057)the Zhejiang Provincial Natural Science Foundation of China(LY18A050002,LY19A050001)the Ten Thousand Talent Program of Zhejiang province(2018R52017)。
文摘By incorporating an iso spin-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 Esym(ρ)on the elliptic flow v2 in197Au+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 Esym(ρ),and the variation of m*n-p ranging from-0.03 to 0.03 at saturation density with isospin asymmetryδ=(ρn-ρp)/ρ-0.2,the Esym(ρ)has a stronger influence on the difference in v2 between neutrons and protons,i.e.,v2n-v2p,than m*n-p has.Meanwhile,at lower beam energies(≤0.25 GeV/nucleon),v2n-v2p is sensitive to both the Esym(ρ)and the m*n-p.Moreover,the influence of m*n-p on v2n-v2p is more evident with the parameters of this study when using the soft,rather than stiff,symmetry energy.
