Transition density of the large mass hyperon star

The difference between the transition density of a larger mass hyperon star(for example,the neutron star PSR J1614-2230)and that of a smaller mass hyperon star is investigated in the framework of the relativistic mean field theory.We see that the transition density poH increases with the increase of xw(i.e.the mass of the neutron star).For the nucleons parts,the neutrons make the main contribution to the transition density as the baryon density p=poH.With the increase of the x_ω(i.e.the mass of the neutron star),the relative particle number density of neutrons decreases while that of protons increases.For the parts of hyperons,the A andΣ~-make the main contributions to the transition density as the baryon density p=pOH.The relative particle number density of A decreases while that of E~increases with the increase of the x_ω(i.e.the mass of the neutron star).For the hyperonsΣ~-,Σ~0 and E~-,the total contributions are less than 16 per cent.     

The Surface Gravitational Redshift of a Proto Neutron Star

The influence of the δ and Ф mesons on the surface gravitational redshift of a proto neutron star is investigated within the framework of relativistic mean field theory for the baryon octet： {n, p, A, ∑-, ∑0 ,∑＋, , 0} system. It is found that, compared with those without considering the contribution of σ and Ф mesons, the surface gravitational redshift decreases, corresponding to the maximum value of the mass decreasing from 0.2220 to 0.1937, about 12.7%. It is also found that the appearance of σ and Ф mesons makes the surface gravitational redshift as a function of M/R decrease too, with M and R being the mass and radius of the proto neutron star.     

f0（975）和Ф（1020）介子对中子星物质的影响

利用相对论平均场理论，考虑了σ＊，Ф介子及重子八重态{N，P，A，∑^-，∑0,∑＋，Ξ^-，Ξ^0}，研究了中子星的性质．发现当考虑了σ＊，Ф介子的贡献时，超子出现的临界重子数密度降低了，超子数目增加了，超子星的转变密度poH降低了，物态方程变软，最大质量变小而相应的中子星半径增大，中子星的中心重子数密度、中心能量密度和中心压强均降低．     

Effect of the mesons σ~＊ and Φ and the variety of U_Σ~（N） on the transition density of hyperon stars

The effect of the mesons σ＊ and Φ and the variety of UΣ（N ）on the transition density of hyperon stars is examined within the framework of relativistic mean field theory for the baryon octet {n,p,Λ,Σ-,Σ0,Σ＋,Ξand Ξ0} system.It is found that,compared with that without considering the mesons σ＊ and Φ,the transition density of hyperon stars decreases,the critical baryon density that hyperons Σ-,Σ0,Σ＋,Ξand Ξ0 appears to decrease too,but for Λ the effect is not obvious.As U Σ（N ）goes up,the critical baryon density of Σ＋,Σ0 and Σincreases,that of Ξ0 decreases and that of Λ and Ξis fixed.In addition,it is found that the variety of UΣ（N ）almost does not influence the transition density.     

f0(975)和φ(1020)介子对中子星物质的影响

利用相对论平均场理论,考虑了σ*,φ介子及重子八重态{N,P,A,∑-,∑0,∑ ,(I)-,(I)0},研究了中子星的性质.发现当考虑了σ*,φ介子的贡献时,超子出现的临界重子数密度降低了,超子数目增加了,超子星的转变密度ρ0H降低了,物态方程变软,最大质量变小而相应的中子星半径增大,中子星的中心重子数密度、中心能量密度和中心压强均降低.     

A set of new nucleon coupling constants and the proto neutron star matter

Using a new set of nucleon coupling constants CZ11 the properties of a proto neutron star are examined within the framework of the relativistic mean-field theory for the baryon octet system.It is found that the relative number density of Λ,Ξ-,and Ξ0 for CZ11 are all smaller than those for GL97 and for both CZ11 and GL97,Σ-,Σ0,and Σ+ do not appear.It is also found that the pressure and the maximum mass for CZ11 are all smaller than those for GL97.The maximum mass for CZ11 decreases by approximately 9 percent compared with that for GL97.     

Effects of σ* and Φ mesons on the surface redshift of a neutron star

The effects of σ and Φ mesons on the surface redshift of a neutron star have been investigated within the framework of relativistic mean field theory for the baryon octet {n,p,Λ,Σ,Σ 0,Σ +,Ξ,Ξ 0 } system.It is found that compared with those without considering the contributions of σ and Φ mesons,the surface redshift decreases and that corresponding to the maximum value of the mass also decreases from 0.2540 to 0.2236,about by 12%.Meanwhile,it is also found that including σ and Φ mesons,the M/R and that corresponding to the maximum mass decrease.     

σ和φ介子对有限温度中子星物质的影响

考虑到σ*,φ介子的贡献及重子八重态{n,p,Λ,Σ^－,Σ⁰,Σ⁺,Ξ^－,Ξ⁰}, 采用相对论平均场方法,在5—25MeV的有限温度范围内, 对中子星物质的性质进行了研究. 发现当考虑到σ*,φ介子的贡献后, 超子出现的临界密度降低了(但对Λ超子, 影响并不显著), 超子的粒子数密度增加了, 在能量密度较高时物态方程变软, 中子星的最大质量变小而相应的半径增大, 中子星的中心粒子数密度、中心能量密度和中心压强都降低了. 当温度为较低的T=5MeV, 10MeV时, σ*,φ介子的参与使出现Σ⁰,Ξ⁰,Σ⁺超子的临界密度极大地降低了; 但当温度为较高的T=15MeV, 20MeV, 25MeV时, 影响则较小. 对于Λ,Σ^－,Ξ^－超子来说, 在上述所有温度下, σ*,φ介子对超子出现的临界密度的影响都不明显.     

σ^＊和Ф介子对有限温度中子星物质的影响

考虑到矿，中介子的贡献及重子八重态{n，p，∧，∑^-，∑^0，∑^＋，≡^-，≡^0}，采用相对论平均场方法，在5—25MeV的有限温度范围内，对中子星物质的性质进行了研究．发现当考虑到σ^＊，Ф介子的贡献后，超子出现的临界密度降低了（但对∧超子，影响并不显著），超子的粒子数密度增加了，在能量密度较高时物态方程变软，中子星的最大质量变小而相应的半径增大，中子星的中心粒子数密度、中心能量密度和中心压强都降低了．当温度为较低的T=5MeV，10MeV时，σ^＊，Ф介子的参与使出现∑^0，≡^0，∑^＋超子的临界密度极大地降低了；但当温度为较高的T=15MeV，20MeV，25MeV时，影响则较小．对于∧，∑^-，≡^-超子来说，在上述所有温度下，矿，中介子对超子出现的临界密度的影响都不明显．