With the emphasis on the effects of the density-dependent bag constant and the rotation of strange star the limiting mass of strange star is calculated. The obtained results show that the limiting mass and the corresp...With the emphasis on the effects of the density-dependent bag constant and the rotation of strange star the limiting mass of strange star is calculated. The obtained results show that the limiting mass and the corresponding radius of strange star increase as the rotation frequency increases, and tend to be lowered when the density-dependent bag constant is considered.展开更多
Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron s...Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron stars, respectively. Our results indicate that the onset of hadron-quark phase transition is put off and the appearance of hyperon species is increased with the increase in bag constant. As a result, the hybrid star equation of state for a mixed phase range stiffens whereas that of the quark phase range softens, and the gravitational mass as well as the corresponding radius of hybrid stars are increased obviously. The gravitational mass of a hybrid star is increased from 1.42 M （M is solar mass） to 1.63M and the corresponding radius is changed from 9.1 km to 12.2 km when the bag constant （B1/4） is increased from 170 MeV to 200 MeV. It is interesting to find that hybrid star equations of state become non-smooth when the TM2 parameter sets in the framework of relativistic mean field theory used to describe the hadronic matter, and consequently, the third family of compact stars appear in the mass-radius relations of hybrid stars in the narrow scope of the bag constant from 175 MeV to 180 MeV. These show that the choice of the bag constant in the MIT bag model has significant influence on the properties of hybrid stars.展开更多
We study the quark loop effects on the dressed gluon propagator and also on the quark propagator itself.We find that the gluon propagators are different in two phases.The quark mass effects on the gluon propagator are...We study the quark loop effects on the dressed gluon propagator and also on the quark propagator itself.We find that the gluon propagators are different in two phases.The quark mass effects on the gluon propagator aresmall but not negligible.We also study the current quark mass dependence on the bag constant.展开更多
The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark ph...The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark phase （QP）, respectively. We find that the density-dependent B（p） decreases with baryon density p; this decrement makes the strange quark matter become more energetically favorable than ever, which makes the threshold densities of the hadron-quark phase transition lower than those of the original bag constant case. In this case, the hyperon degrees of freedom can not be considered. As a result, the equations of state of a star in the mixed phase （MP） become softer whereas those in the QP become stiffer, and the radii of the star obviously decrease. This indicates that the extended MIT bag model is more suitable to describe hybrid stars with small radii.展开更多
文摘With the emphasis on the effects of the density-dependent bag constant and the rotation of strange star the limiting mass of strange star is calculated. The obtained results show that the limiting mass and the corresponding radius of strange star increase as the rotation frequency increases, and tend to be lowered when the density-dependent bag constant is considered.
基金Supported by the National Natural Science Foundation of China (10275029, 10675054)Natural Science Foundation of Henan Education Department (2008A140009)+1 种基金Science Foundation of Nanyang Normal University (nytc2006k98)Natural Science Foundation of Henan Province (112300410187)
文摘Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron stars, respectively. Our results indicate that the onset of hadron-quark phase transition is put off and the appearance of hyperon species is increased with the increase in bag constant. As a result, the hybrid star equation of state for a mixed phase range stiffens whereas that of the quark phase range softens, and the gravitational mass as well as the corresponding radius of hybrid stars are increased obviously. The gravitational mass of a hybrid star is increased from 1.42 M （M is solar mass） to 1.63M and the corresponding radius is changed from 9.1 km to 12.2 km when the bag constant （B1/4） is increased from 170 MeV to 200 MeV. It is interesting to find that hybrid star equations of state become non-smooth when the TM2 parameter sets in the framework of relativistic mean field theory used to describe the hadronic matter, and consequently, the third family of compact stars appear in the mass-radius relations of hybrid stars in the narrow scope of the bag constant from 175 MeV to 180 MeV. These show that the choice of the bag constant in the MIT bag model has significant influence on the properties of hybrid stars.
文摘We study the quark loop effects on the dressed gluon propagator and also on the quark propagator itself.We find that the gluon propagators are different in two phases.The quark mass effects on the gluon propagator aresmall but not negligible.We also study the current quark mass dependence on the bag constant.
基金National Natural Science Foundation of China (10275029, 10675054)Natural Science Foundation of Henan Education Department(2008A140009)The Science Foundation of Nanyang Normal University
文摘The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark phase （QP）, respectively. We find that the density-dependent B（p） decreases with baryon density p; this decrement makes the strange quark matter become more energetically favorable than ever, which makes the threshold densities of the hadron-quark phase transition lower than those of the original bag constant case. In this case, the hyperon degrees of freedom can not be considered. As a result, the equations of state of a star in the mixed phase （MP） become softer whereas those in the QP become stiffer, and the radii of the star obviously decrease. This indicates that the extended MIT bag model is more suitable to describe hybrid stars with small radii.
