EFFECTS OF Δ-BARYON INTERACTION STRENGTH ON NEUTRON STARS PROPERTIES

2007 ◽  
Vol 16 (02n03) ◽  
pp. 175-183 ◽  
Author(s):  
J. C. T. DE OLIVEIRA ◽  
S. B. DUARTE ◽  
H. RODRIGUES ◽  
M. CHIAPPARINI ◽  
M. KYOTOKU
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Mean Field Theory ◽  
Mean Field ◽  
Interaction Strength ◽  
Hadronic Matter ◽  
Resonance Neutron ◽  
Baryon Interaction ◽  
Relativistic Mean Field ◽  
Central Regions

We investigate the effect of Δ-resonance interaction strength on the equation of state of asymmetric hadronic matter and neutron stars structure. We discuss Δ-matter formation at high densities in the context of a relativistic mean field theory. We show that the attractive nature of the Δ-baryon interaction can induce a phase transition accompanying Δ-matter formation, at values of densities presumably existing in central regions of neutron stars. The possibility of a rich Δ-resonance neutron star is presented using the proposed equation of state.

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.

scholarly journals Phases of Hadron-Quark Matter in (Proto) Neutron Stars

Universe ◽  
2019 ◽  
Vol 5 (7) ◽  
pp. 169 ◽  
Author(s):  
Fridolin Weber ◽  
Delaney Farrell ◽  
William M. Spinella ◽  
Germán Malfatti ◽  
Milva G. Orsaria ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Quark Matter ◽  
Mean Field Theory ◽  
Mean Field ◽  
Hadronic Matter ◽  
Relativistic Mean Field ◽  
Quark Flavor ◽  
Flavor Mixing ◽  
Non Local ◽  
Quark Deconfinement

In the first part of this paper, we investigate the possible existence of a structured hadron-quark mixed phase in the cores of neutron stars. This phase, referred to as the hadron-quark pasta phase, consists of spherical blob, rod, and slab rare phase geometries. Particular emphasis is given to modeling the size of this phase in rotating neutron stars. We use the relativistic mean-field theory to model hadronic matter and the non-local three-flavor Nambu–Jona-Lasinio model to describe quark matter. Based on these models, the hadron-quark pasta phase exists only in very massive neutron stars, whose rotational frequencies are less than around 300 Hz. All other stars are not dense enough to trigger quark deconfinement in their cores. Part two of the paper deals with the quark-hadron composition of hot (proto) neutron star matter. To this end we use a local three-flavor Polyakov–Nambu–Jona-Lasinio model which includes the ’t Hooft (quark flavor mixing) term. It is found that this term leads to non-negligible changes in the particle composition of (proto) neutron stars made of hadron-quark matter.

FINITE TEMPERATURE EQUATIONS OF STATE FOR MIXED STARS

2004 ◽  
Vol 13 (07) ◽  
pp. 1249-1253
Author(s):  
DÉBORA P. MENEZES ◽  
C. PROVIDÊNCIA
Keyword(s):  
Field Theory ◽  
Neutron Stars ◽  
Quark Matter ◽  
Finite Temperature ◽  
Equations Of State ◽  
Mean Field Theory ◽  
Mean Field ◽  
Relativistic Mean Field Theory ◽  
Relativistic Mean Field

We investigate the properties of mixed stars formed by hadronic and quark matter in β-equilibrium described by appropriate equations of state (EOS) in the framework of relativistic mean-field theory. The calculations were performed for T=0 and for finite temperatures and also for fixed entropies with and without neutrino trapping in order to describe neutron and proto-neutron stars. The star properties are discussed. Maximum allowed masses for proto-neutron stars are much larger when neutrino trapping is imposed.

scholarly journals Kaon condensation and equation of state in the relativistic mean-field theory

1994 ◽  
Vol 337 (1-2) ◽  
pp. 19-24 ◽  
Author(s):  
Tomoyuki Maruyama ◽  
Hirotsugu Fujii ◽  
Takumi Muto ◽  
Toshitaka Tatsumi
Keyword(s):  
Field Theory ◽  
Equation Of State ◽  
Mean Field Theory ◽  
Mean Field ◽  
Relativistic Mean Field Theory ◽  
Relativistic Mean Field ◽  
Kaon Condensation

THE ROLE OF THE NUCLEAR MATTER COMPRESSION MODULUS IN NEUTRON STARS

2004 ◽  
Vol 13 (07) ◽  
pp. 1519-1524 ◽  
Author(s):  
VERÔNICA A. DEXHEIMER ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
MOISÉS RAZEIRA ◽  
MANFRED DILLIG
Keyword(s):  
Neutron Stars ◽  
Nuclear Matter ◽  
Body Problem ◽  
Mean Field Theory ◽  
Mean Field ◽  
Compression Modulus ◽  
Baryon Number ◽  
Many Body ◽  
Relativistic Mean Field

For the nuclear many body problem at high densities, formulated in the framework of a relativistic mean-field theory, we investigate in detail the compression modulus of nuclear matter as a function of the effective nucleon mass. We include consistently in our modelling chemical equilibrium as well as baryon number and electric charge conservation and investigate properties of neutron stars. Among other predictions we focus on the dependence of the maximum mass of a sequence of neutron stars as a function of the compression modulus and the nucleon effective mass.

Covariant Equation of State for Two Colliding Nuclear Matters in the Relativistic Meson Field Theory

1997 ◽  
Vol 06 (01) ◽  
pp. 151-159 ◽  
Author(s):  
M. Rashdan
Keyword(s):  
Field Theory ◽  
Equation Of State ◽  
Nonlinear Models ◽  
Mean Field Theory ◽  
Mean Field ◽  
Heavy Ion ◽  
Ion Scattering ◽  
Relativistic Mean Field ◽  
Heavy Ion Scattering ◽  
Covariant Equation

The relativistic mean field theory (linear and nonlinear) models are extended to the case of two colliding nuclear matters, relevant to heavy ion scattering and reactions. The effect of vacuum corrections is taken into account through the relativistic Hartree approximation. The Fermi sea is assumed to consist of two colliding Lorentz elongated spheres. A relativistic covariant Pauli correction is considered for the overlap case. This relativistic Pauli correction is found to be very important due to its dependence on the effective nucleon mass which strongly depends on the model equation of state. It is found that by increasing the velocity the energy per baryon increases and saturates at higher densities. The increase in the energy per baryon at low density (the region of no overlap) is much larger than that at high density (the region of large overlap), due to Pauli correction effects. The saturation density of the nonlinear model is shifted to larger values than that of the linear model. Vacuum corrections effects are found to reduce largely te overlap region.

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