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Title: Antikaon condensation and deconfinement phase transition in neutron stars

Abstract

Antikaon condensation and deconfinement phase transition in neutron stars are investigated in a chiral hadronic model (also referred as to the FST model) for the hadronic phase and in the MIT bag model for the deconfined quark matter phase. It is shown that the existence of quark matter phase makes antikaon condensation impossible in neutron stars. The properties of neutron stars are sensitive to the bag constant. For the small values of the bag constant, the pure quark matter core appears and hyperons are strongly suppressed in neutron stars, whereas for the large bag constant, the hadron-quark mixed phase exists in the center of neutron stars. The maximum masses of neutron stars with the quark matter phase are lower than those without the quark matter phase; meanwhile, the maximum masses of neutron stars with the quark matter phase increase with the bag constant.

Authors:
 [1]; ;  [1];  [2];  [3];  [2];  [1];  [2];  [2]
  1. Department of Technical Physics and MOE Laboratory of Heavy Ion Physics, Peking University, Beijing 100871 (China)
  2. (China)
  3. Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China)
Publication Date:
OSTI Identifier:
20771561
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.73.055803; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANTIKAONS; BAG MODEL; BOSE-EINSTEIN CONDENSATION; CHIRALITY; HYPERONS; MASS; NEUTRON STARS; PHASE TRANSFORMATIONS; QUARK MATTER; QUARKS

Citation Formats

Gu Jianfa, Guo Hua, Xu Furong, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, Li Xiguo, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Liu Yuxin, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, and Department of Physics, Peking University, Beijing 100871. Antikaon condensation and deconfinement phase transition in neutron stars. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.055803.
Gu Jianfa, Guo Hua, Xu Furong, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, Li Xiguo, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Liu Yuxin, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, & Department of Physics, Peking University, Beijing 100871. Antikaon condensation and deconfinement phase transition in neutron stars. United States. doi:10.1103/PhysRevC.73.055803.
Gu Jianfa, Guo Hua, Xu Furong, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, Li Xiguo, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Liu Yuxin, Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, and Department of Physics, Peking University, Beijing 100871. Mon . "Antikaon condensation and deconfinement phase transition in neutron stars". United States. doi:10.1103/PhysRevC.73.055803.
@article{osti_20771561,
title = {Antikaon condensation and deconfinement phase transition in neutron stars},
author = {Gu Jianfa and Guo Hua and Xu Furong and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 and Li Xiguo and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 and Liu Yuxin and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 and Department of Physics, Peking University, Beijing 100871},
abstractNote = {Antikaon condensation and deconfinement phase transition in neutron stars are investigated in a chiral hadronic model (also referred as to the FST model) for the hadronic phase and in the MIT bag model for the deconfined quark matter phase. It is shown that the existence of quark matter phase makes antikaon condensation impossible in neutron stars. The properties of neutron stars are sensitive to the bag constant. For the small values of the bag constant, the pure quark matter core appears and hyperons are strongly suppressed in neutron stars, whereas for the large bag constant, the hadron-quark mixed phase exists in the center of neutron stars. The maximum masses of neutron stars with the quark matter phase are lower than those without the quark matter phase; meanwhile, the maximum masses of neutron stars with the quark matter phase increase with the bag constant.},
doi = {10.1103/PhysRevC.73.055803},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 73,
place = {United States},
year = {Mon May 15 00:00:00 EDT 2006},
month = {Mon May 15 00:00:00 EDT 2006}
}
  • We study the properties of strange quark matter in equilibrium with normal nuclear matter. Instead of using the conventional bag model in quark sector, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates. In nuclear matter, we adopt the equation of state from the Brueckner-Bethe-Goldstone approach with three-body forces. It is found that the mixed phase can occur, for a reasonable confinement parameter, near the normal nuclear saturation density and goes over to pure quark matter at about 5 times the saturation. The onset of mixed and quark phases is compatible with the observed classmore » of low-mass neutron stars, but it hinders the occurrence of kaon condensation.« less
  • We study the effects of strong magnetic fields on antikaon condensation in neutron star matter using the quark-meson coupling (QMC) model. The QMC model describes a nuclear many-body system as nonoverlapping MIT bags in which quarks interact through the self-consistent exchange of scalar and vector mesons in the mean-field approximation. It is found that the presence of strong magnetic fields alters the threshold density of antikaon condensation significantly. The onset of K{sup -} condensation stronger depends on the magnetic field strength, and it even shifts beyond the threshold of K{sup 0} condensation for sufficiently strong magnetic fields. In the presencemore » of strong magnetic fields, the equation of state (EOS) becomes stiffer in comparison with the field-free case. The softening of the EOS by antikaon condensation also depends on the magnetic field strength, and it becomes less pronounced with increasing magnetic field strength. The results of the QMC model are compared with those obtained in a relativistic mean-field (RMF) model, and we find there are quantitative differences between the results of the QMC and RMF models.« less
  • The relativistic mean field approach including isovector-scalar channel (i.e., exchanging {delta} mesons) interaction is taken to study the properties of neutron star matter including hyperons and antikaon condensation. For hyperonic neutron stars, it shows that the {delta}-meson channel interaction stiffens the equation of state at lower densities but it softens the equation of state after hyperons appear. This leads to the neutron star having a lower central density and a larger radius than the one with the same mass but without the {delta}-meson channel interaction. For neutron star matter including both hyperons and antikaon condensation, the {delta}-meson channel interaction increasesmore » the onset density of the antikaon condensation. At the same time, the stability of the kaonic neutron star and its dependence on the kaon optical potential are discussed. For stable kaonic neutron stars with larger radii, those with the inclusion of the {delta}-meson channel interaction have larger masses than those without the {delta}-meson interaction, but the result is reversed for those with smaller radii. Calculated results are also compared with neutron star observations. Constraints on the model parameters are then provided.« less
  • No abstract prepared.
  • It is shown that in nuclear matter at Z = N for density n < n/sub 0/ (n/ sub 0/ nuclear density) an electrically neutral condensate of pi /sup +/, pi / sup /, pi /sup o/ - mesons arises. The results of the calculations for the case of the neutron star (Z << N) are given. In this case there are two phase transitions: one corresponds to pi 0 condensation, and the second, to the electrically neutral pi /sup +/, pi /sup -/ condensation. The pi /sup -/ condensate apparently does not appear even at very high densities. (auth)