Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the iso...Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the isospin emission in heavy-ion collisions is investigated thoroughly.It is found that the yield ratios of energetic neutrons to protons squeezed out during the compression stage of two colliding nuclides are sensitive to the isospin splitting.The elliptic flows of free nucleons are also to be promising observables for extracting the nucleon effective mass splitting.Further experimental measurements are being expected,in particular at the CSR-CEE platform in Lanzhou.Several observables are proposed for constraining the density dependence of symmetry energy,such as the transverse flow difference of neutrons and protons,double ratios of n/p and π-/π+,excitation functions of π-/π+ and K0/K+.展开更多
We investigate the isospin splitting of neutron and proton effective masses in neutron-rich nuclear matter by using Brueckner-Hartree-Fock (BHF) approach and the extended BHF (EBHF) approach including the ground state...We investigate the isospin splitting of neutron and proton effective masses in neutron-rich nuclear matter by using Brueckner-Hartree-Fock (BHF) approach and the extended BHF (EBHF) approach including the ground state correlation contributions. The realistic nucleon-nucleon interaction adopted in our calculation is the Argonne V18 two-body force supplemented with a microscopic three-body force constructed from the meson-exchange current approach. The result is reported in Fig. 1 where the neutron and proton effective masses are plotted as functions of isospin asymmetry parameterβ. It is shown that in both cases by adopting the BHF and EBHF approaches, the predicted neutron effective mass is greater展开更多
本文讨论了当前天文观测中中子星最大质量、1.4倍太阳质量中子星半径、潮汐形变以及声速限制等对状态方程的约束.如果3倍饱和密度以上状态方程的多方参数取γ=2.9,同时使用上述四种限制约束的Skyrme相互作用下的核物质参数的均值和偏差...本文讨论了当前天文观测中中子星最大质量、1.4倍太阳质量中子星半径、潮汐形变以及声速限制等对状态方程的约束.如果3倍饱和密度以上状态方程的多方参数取γ=2.9,同时使用上述四种限制约束的Skyrme相互作用下的核物质参数的均值和偏差为:不可压缩模量K_(0)=243.4±22.0 MeV;对称能因子S_(0)=29.3±2.9 MeV;对称能斜率L=74.4±14.8 Me V;同位旋标量有效质量m_(s)^(*)/m=0.79±0.13;有效质量劈裂参数fI=0.08±0.30(中子有效质量小于质子的有效质量).当考虑3倍饱和密度以上状态方程的多方参数取γ=2.45–2.9时,约束出的K_(0)均值增加了11%,S0均值降低了2%,L均值减少了20%,m_(s)^(*)/m均值降低了4%,但是参数f_(I)均值减小了88%.特别是,如果仅利用中子星的质量小于2.05M_(⊙)的数据来进行约束,发现其所需的参数组对应的中子有效质量大于质子有效质量.不同中子星质量区约束出的f_(I)符号的差异表明,未来进一步约束有效的Skyrme相互作用的状态方程的参数还需结合重离子碰撞分析.展开更多
基金Supported by National Natural Science Foundation of China(NSFC) projects (No.11175218)the Advancement Society of Young Innovation of Chinese Academy of Sciences
文摘Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the isospin emission in heavy-ion collisions is investigated thoroughly.It is found that the yield ratios of energetic neutrons to protons squeezed out during the compression stage of two colliding nuclides are sensitive to the isospin splitting.The elliptic flows of free nucleons are also to be promising observables for extracting the nucleon effective mass splitting.Further experimental measurements are being expected,in particular at the CSR-CEE platform in Lanzhou.Several observables are proposed for constraining the density dependence of symmetry energy,such as the transverse flow difference of neutrons and protons,double ratios of n/p and π-/π+,excitation functions of π-/π+ and K0/K+.
文摘We investigate the isospin splitting of neutron and proton effective masses in neutron-rich nuclear matter by using Brueckner-Hartree-Fock (BHF) approach and the extended BHF (EBHF) approach including the ground state correlation contributions. The realistic nucleon-nucleon interaction adopted in our calculation is the Argonne V18 two-body force supplemented with a microscopic three-body force constructed from the meson-exchange current approach. The result is reported in Fig. 1 where the neutron and proton effective masses are plotted as functions of isospin asymmetry parameterβ. It is shown that in both cases by adopting the BHF and EBHF approaches, the predicted neutron effective mass is greater
文摘本文讨论了当前天文观测中中子星最大质量、1.4倍太阳质量中子星半径、潮汐形变以及声速限制等对状态方程的约束.如果3倍饱和密度以上状态方程的多方参数取γ=2.9,同时使用上述四种限制约束的Skyrme相互作用下的核物质参数的均值和偏差为:不可压缩模量K_(0)=243.4±22.0 MeV;对称能因子S_(0)=29.3±2.9 MeV;对称能斜率L=74.4±14.8 Me V;同位旋标量有效质量m_(s)^(*)/m=0.79±0.13;有效质量劈裂参数fI=0.08±0.30(中子有效质量小于质子的有效质量).当考虑3倍饱和密度以上状态方程的多方参数取γ=2.45–2.9时,约束出的K_(0)均值增加了11%,S0均值降低了2%,L均值减少了20%,m_(s)^(*)/m均值降低了4%,但是参数f_(I)均值减小了88%.特别是,如果仅利用中子星的质量小于2.05M_(⊙)的数据来进行约束,发现其所需的参数组对应的中子有效质量大于质子有效质量.不同中子星质量区约束出的f_(I)符号的差异表明,未来进一步约束有效的Skyrme相互作用的状态方程的参数还需结合重离子碰撞分析.
