摘要
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y=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K0=243.4±22.0 MeV;对称能因子S0=29.3±2.9 MeV;对称能斜率L=74.4±14.8 MeV;同位旋标量有效质量m*/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y=2.45-2.9时,约束出的K0均值增加了 11％,S0均值降低了 2％,L均值减少了 20％,ms*/m均值降低了4％,但是参数fI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fI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.
Abstract
In this paper,we apply Bayesian inference to constrain the nuclear equation of state parameters by using properties of neutron stars,including the maximum neutron star mass,radius,tidal deformability at 1.4 times the solar mass,and speed of sound.When the polytrope EOS parameter γ is fixed at 2.9 and above four astronomical observations are simultaneously used,the mean values and uncertainties of the nuclear matter parameters derived from standard Skyrme interactions are as follows:incompressibility K0=243.4±22.0 MeV,symmetry energy coefficient S0=29.3±2.9 MeV,the slope of symmetry energy L=74.4±14.8 MeV,the isoscalar effective mass m*s/m=0.79±0.13,and a quantity related to effective mass splitting fI=0.08±0.30(when fI＞0,this implies that the effective mass of neutrons is less than that of protons).When considering the uncertainty of γ in the range of 2.45-2.9,we found that K0 increased by 11％,S0 decreased by 2％,L decreased by 20％,m*s/m decreased by 4％,and the averaged value of fI reduced by 88％.Particularly,if constraints are based solely on neutron star masses less than 2.05 M☉,the preferred effective Skyrme interactions exhibit a neutron effective mass greater than the proton effective mass,i.e.,fI＜0.The inverse sign of the constrained f1 implies that reducing the uncertainties of the effective Skyrme interaction parameters needs combination analysis with heavy-ion collisions in future studies.
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