THE EFFECT OF THE SCALAR-ISOVECTOR MESON FIELD ON HYPERON-RICH NEUTRON STAR MATTER

2008 ◽  
Vol 17 (07) ◽  
pp. 1293-1307 ◽  
Author(s):  
AI-JUN MI ◽  
WEI ZUO ◽  
ANG LI
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Mean Field Theory ◽  
Mean Field ◽  
Maximum Mass ◽  
Meson Field ◽  
Neutron Star Matter ◽  
Relativistic Mean Field ◽  
Strangeness Content ◽  
Positively Charged

We investigate the effect of the scalar-isovector δ-meson field on the equation of state (EOS) and composition of hyperonic neutron star matter, and the properties of hyperonic neutron stars within the framework of the relativistic mean field theory. The influence of the δ-field turns out to be quite different and generally weaker for hyperonic neutron star matter as compared to that for npeμ neutron star matter. We find that inclusion of the δ-field enhances the strangeness content slightly and consequently moderately softens the EOS of neutron star matter in its hyperonic phase. As for the composition of hyperonic star matter, the effect of the δ-field is shown to shift the onset of the negatively-charged (positively-charged) hyperons to slightly lower (higher) densities and to enhance (reduce) their abundances. The influence of the δ-field on the maximum mass of hyperonic neutron stars is found to be fairly weak, whereas inclusion of the δ-field turns out to enhance sizably both the radii and the moments of inertia of neutron stars with given masses. It is also shown that the effects of the δ-field on the properties of hyperonic neutron stars remain similar in the case of switching off the Σ hyperons.

NEUTRON STARS WITH KAON CONDENSATION IN RELATIVISTIC EFFECTIVE MODEL

2013 ◽  
Vol 22 (05) ◽  
pp. 1350026 ◽  
Author(s):  
CHEN WU ◽  
WEI-LIANG QIAN ◽  
YU-GANG MA ◽  
JI-FENG YANG
Keyword(s):  
Field Theory ◽  
Neutron Star ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Optical Potential ◽  
Mean Field Theory ◽  
Mean Field ◽  
Neutron Star Matter ◽  
Relativistic Mean Field ◽  
Kaon Condensation

Relativistic mean-field theory with parameter sets FSUGold and IU-FSU is extended to study the properties of neutron star matter in β equilibrium by including Kaon condensation. The mixed phase of normal baryons and Kaon condensation cannot exist in neutron star matter for the FSUGold model and the IU-FSU model. In addition, it is found that when the optical potential of the K- in normal nuclear matter UK ≳ -100 MeV , the Kaon condensation phase is absent in the inner cores of the neutron stars.

scholarly journals STRUCTURE AND PROPERTIES OF NEUTRON STARS IN THE RELATIVISTIC MEAN-FIELD THEORY

2001 ◽  
Vol 10 (05) ◽  
pp. 607-624 ◽  
Author(s):  
ILONA BEDNAREK ◽  
RYSZARD MANKA
Keyword(s):  
Field Theory ◽  
Neutron Star ◽  
Neutron Stars ◽  
Mean Field Theory ◽  
Mean Field ◽  
Neutron Star Matter ◽  
Relativistic Mean Field Theory ◽  
X Ray ◽  
Relativistic Mean Field ◽  
Bulk Parameters

Properties of rotating neutron stars with the use of relativistic mean-field theory are considered. The performed analysis of neutron star matter is based on the nonlinear Lgrangian density. The presence of nonlinear interaction of vector mesons modifies the density dependence of the ρ field and influences bulk parameters of neutron stars. The observed quasiperiodic X-ray oscillations of low mass X-ray binaries can be used in order to constrain the equation of state of neutron star matter. Having assumed that the maximum frequency of the quasiperiodic oscillations originates at the circular orbit it is possible to estimate masses and radii of neutron stars.

scholarly journals Constraints on Microscopic and Phenomenological Equations of State of Dense Matter from GW170817

Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 204 ◽  
Author(s):  
Domenico Logoteta ◽  
Ignazio Bombaci
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Equations Of State ◽  
Mean Field ◽  
Dense Matter ◽  
Neutron Star Matter ◽  
Field Approach ◽  
Relativistic Mean Field ◽  
Three Body ◽  
Good Agreement

We discuss the constraints on the equation of state (EOS) of neutron star matter obtained by the data analysis of the neutron star-neutron star merger in the event GW170807. To this scope, we consider two recent microscopic EOS models computed starting from two-body and three-body nuclear interactions derived using chiral perturbation theory. For comparison, we also use three representative phenomenological EOS models derived within the relativistic mean field approach. For each model, we determine the β -stable EOS and then the corresponding neutron star structure by solving the equations of hydrostatic equilibrium in general relativity. In addition, we calculate the tidal deformability parameters for the two neutron stars and discuss the results of our calculations in connection with the constraints obtained from the gravitational wave signal in GW170817. We find that the tidal deformabilities and radii for the binary’s component neutron stars in GW170817, calculated using a recent microscopic EOS model proposed by the present authors, are in very good agreement with those derived by gravitational waves data.

HADRON-QUARK PHASE TRANSITION AND ANTIKAON CONDENSATION IN NEUTRON STARS

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2481-2484
Author(s):  
H. SHEN ◽  
F. YANG ◽  
P. YUE
Keyword(s):  
Field Theory ◽  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Mean Field Theory ◽  
Mean Field ◽  
Maximum Mass ◽  
Relativistic Mean Field ◽  
The Core ◽  
Quark Phase

We study the hadron-quark phase transition and antikaon condensation which may occur in the core of massive neutron stars. The relativistic mean field theory is used to describe the hadronic phase, while the Nambu-Jona-Lasinio model is adopted for the quark phase. We find that the hadron-quark phase transition is very sensitive to the models used. The appearance of deconfined quark matter and antikaon condensation can soften the equation of state at high density and lower the maximum mass of neutron stars.

Magnetic field and EoS of neutron star matter at finite temperature

2015 ◽  
Vol 24 (07) ◽  
pp. 1550051
Author(s):  
Qingwu Wang ◽  
Xiaofu Lü
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Finite Temperature ◽  
Mean Field Theory ◽  
Mean Field ◽  
Mass Term ◽  
Baryon Density ◽  
Neutron Star Matter ◽  
Relativistic Mean Field ◽  
Inflection Points

In this paper, magnetic field and equation of state (EoS) of neutron star matter are studied under relativistic mean field theory. A nonzero mass term of magnetic field in the Lagrangian is introduced, which depends on baryon density of charged particles. The magnetic field has not been treated as external as usual and the calculations of magnetic field strength at finite temperature reveal the existence of inflection points in certain densities.

scholarly journals Searching optimum equations of state of neutron star matter in strong magnetic fields with rotation

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
C Watanabe ◽  
K Yanase ◽  
N Yoshinaga
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Equations Of State ◽  
Mean Field ◽  
Maximum Mass ◽  
Neutron Star Matter ◽  
Solar Mass ◽  
Strong Magnetic Fields ◽  
Relativistic Mean Field ◽  
Rho A

Abstract Masses and radii of neutron stars are obtained in the presence of strong magnetic fields together with rotation. Mass-radius relations are calculated using 11 equations of state (EoSs: GM1, TM1-a, TM1-b, TM2$\omega\rho$-a, TM2$\omega\rho$-b, NL3-a, NL3-b, NL3$\omega\rho$-a, NL3$\omega\rho$-b, DDME2-a and DDME2-b) in relativistic mean field (RMF) theory. Obtained masses are over and around twice the solar mass ($M_\odot$) for all EoSs in the presence of strong magnetic fields of $3 \times 10^{18}$ G at the center. For NL3$\omega\rho$-a and NL3$\omega\rho$-b EoSs, masses are more than $M=2.17\,M_\odot$(observed maximum mass: $2.14\,M_\odot$) even without magnetic fields. Rotational effects are found to be insignificant in any case, at least up to the Kepler frequency. Suitable EoSs are also selected concerning the constraint on the radius of a neutron star.

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