The numerical results of the populations for the baryon octet in neutron star matter have been presented by solving a set transcendental equations in the framework of the relativistic mean field approximation. The inf...The numerical results of the populations for the baryon octet in neutron star matter have been presented by solving a set transcendental equations in the framework of the relativistic mean field approximation. The influence of the hyperon interactions on hyperon populations in neutron star matter is discussed. The results manifest that when the ratio of the hyperon-to-nucleon couplings increases, all hyperons appear towards low baryon density direction.展开更多
We have investigated the possibility of the presence of the deltas in neutron star matter and their effects on neutron stars. Δ-meson couplings of the theoretical predictions are only restricted in a region where the...We have investigated the possibility of the presence of the deltas in neutron star matter and their effects on neutron stars. Δ-meson couplings of the theoretical predictions are only restricted in a region where the deltas can be present and even a first-order phase transition may take place, making the EOS sorer and the maximum mass of neutron stars smaller. The presence of the deltas leads to the rapid decrease of neutrino mean free paths.展开更多
In the relativistic σ-ω model, including the vacuum fluctuation of nucleons and σ mesons, the effect of the temperature to the composition and equation of state of protoneutron star matter, nucleon effective mass a...In the relativistic σ-ω model, including the vacuum fluctuation of nucleons and σ mesons, the effect of the temperature to the composition and equation of state of protoneutron star matter, nucleon effective mass and chemical potential of neutrons and electrons are studied. We find that the influence of the temperature on the equation of state of protoneutron star matter is indeed small, however, its influence on the composition of protoneutron star, which will contribute to the evolution of protoneutron star, cannot be neglected in low density region. The chemical potentials of neutrons and electrons also depend on the temperature in almost the same density region.展开更多
We investigate the neutron star magnetic field by the relative mean-field theory, where the photon effective mass depending on baryon density of charged particles is nonzero. This field is produced by star itself, whi...We investigate the neutron star magnetic field by the relative mean-field theory, where the photon effective mass depending on baryon density of charged particles is nonzero. This field is produced by star itself, which is the function of baryon density. The result fits the observations.展开更多
It is hypothesized that,at low temperature,though atomic nuclei are made of 2-flavored nucleons(i.e.,nucleon matter as nuclear droplet),strongly interacting matter(i.e.,gigantic nucleus)with baryon number from A≃10^(3...It is hypothesized that,at low temperature,though atomic nuclei are made of 2-flavored nucleons(i.e.,nucleon matter as nuclear droplet),strongly interacting matter(i.e.,gigantic nucleus)with baryon number from A≃10^(3-9)to-10^(57)would be composed of 3-flavored strangeons if Nature favors always the flavor symmetry of quarks.According to that logic,strangeon matter with A-10^(57)could manifest in the form of pulsar-like compact stars,and multi-messenger observations with advanced facilities(e.g.,China’s FAST)could eventually provide a disproof/proof.It is worth emphasizing that this point of view,based on established“old physics”(i.e.,the standard model of particle physics),may have particular consequences for understanding our material world,for both normal luminous matter and even the dark sector.展开更多
A detailed description of the baryon direct Urca processes A: n → p + e + ν_e, B: Λ→ p + e + ν_e and C: Ξ^-→Λ + e + ν_e related to the neutron star cooling is given in the relativistic mean field approximatio...A detailed description of the baryon direct Urca processes A: n → p + e + ν_e, B: Λ→ p + e + ν_e and C: Ξ^-→Λ + e + ν_e related to the neutron star cooling is given in the relativistic mean field approximation. The contributions of the reactions B and C on the neutrino luminosity are calculated by means of the relativistic expressions of the neutrino energy losses. Our results show that the total neutrino luminosities of the reactions A, B and C within the mass range(1.603–2.067) M_⊙((1.515–1.840) M_⊙ for TM1 model) for GM1 model are larger than the corresponding values for neutron star without hyperons. Furthermore, although the neutrino emissivity of the reaction A is suppressed with the appearance of the proton ~1S_0 superfluid, the contribution of the reactions B and C can still quicken a massive neutron star cooling. In particular, the reaction C in PSR J1614-2230 and J0348+0432 is not suppressed by the proton ~1S_0 superfluid due to the higher threshold density of the reaction C, which will further speed up the two pulsars cooling.展开更多
基金The project supported by National Natural Science Foundation of China under Grant Nos.10047001 and 10275029+2 种基金the State Key Basic Research Development Program under Grant No.G2000-0774-07the CAS Knowledge Innovation Project under Contract No.KJCX2-SW-N02
文摘The numerical results of the populations for the baryon octet in neutron star matter have been presented by solving a set transcendental equations in the framework of the relativistic mean field approximation. The influence of the hyperon interactions on hyperon populations in neutron star matter is discussed. The results manifest that when the ratio of the hyperon-to-nucleon couplings increases, all hyperons appear towards low baryon density direction.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10575005 and 10435080the Key Grant Project of the Ministry of Education under Grant No.305001
文摘We have investigated the possibility of the presence of the deltas in neutron star matter and their effects on neutron stars. Δ-meson couplings of the theoretical predictions are only restricted in a region where the deltas can be present and even a first-order phase transition may take place, making the EOS sorer and the maximum mass of neutron stars smaller. The presence of the deltas leads to the rapid decrease of neutrino mean free paths.
文摘In the relativistic σ-ω model, including the vacuum fluctuation of nucleons and σ mesons, the effect of the temperature to the composition and equation of state of protoneutron star matter, nucleon effective mass and chemical potential of neutrons and electrons are studied. We find that the influence of the temperature on the equation of state of protoneutron star matter is indeed small, however, its influence on the composition of protoneutron star, which will contribute to the evolution of protoneutron star, cannot be neglected in low density region. The chemical potentials of neutrons and electrons also depend on the temperature in almost the same density region.
基金the Key Research Plan of Theoretical Physics and Cross Science
文摘We investigate the neutron star magnetic field by the relative mean-field theory, where the photon effective mass depending on baryon density of charged particles is nonzero. This field is produced by star itself, which is the function of baryon density. The result fits the observations.
文摘It is hypothesized that,at low temperature,though atomic nuclei are made of 2-flavored nucleons(i.e.,nucleon matter as nuclear droplet),strongly interacting matter(i.e.,gigantic nucleus)with baryon number from A≃10^(3-9)to-10^(57)would be composed of 3-flavored strangeons if Nature favors always the flavor symmetry of quarks.According to that logic,strangeon matter with A-10^(57)could manifest in the form of pulsar-like compact stars,and multi-messenger observations with advanced facilities(e.g.,China’s FAST)could eventually provide a disproof/proof.It is worth emphasizing that this point of view,based on established“old physics”(i.e.,the standard model of particle physics),may have particular consequences for understanding our material world,for both normal luminous matter and even the dark sector.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11447165,11373047,11404336 and U1731240Youth Innovation Promotion Association,CAS under Grant No.2016056the Development Project of Science and Technology of Jilin Province under Grant No.20180520077JH
文摘A detailed description of the baryon direct Urca processes A: n → p + e + ν_e, B: Λ→ p + e + ν_e and C: Ξ^-→Λ + e + ν_e related to the neutron star cooling is given in the relativistic mean field approximation. The contributions of the reactions B and C on the neutrino luminosity are calculated by means of the relativistic expressions of the neutrino energy losses. Our results show that the total neutrino luminosities of the reactions A, B and C within the mass range(1.603–2.067) M_⊙((1.515–1.840) M_⊙ for TM1 model) for GM1 model are larger than the corresponding values for neutron star without hyperons. Furthermore, although the neutrino emissivity of the reaction A is suppressed with the appearance of the proton ~1S_0 superfluid, the contribution of the reactions B and C can still quicken a massive neutron star cooling. In particular, the reaction C in PSR J1614-2230 and J0348+0432 is not suppressed by the proton ~1S_0 superfluid due to the higher threshold density of the reaction C, which will further speed up the two pulsars cooling.
