Hyperonic stars within the Bogoliubov quark meson model for nuclear matter

2019 ◽  
Vol 28 (05) ◽  
pp. 1950034
Author(s):  
Prafulla K. Panda ◽  
Constança Providência ◽  
Steven A. Moszkowski ◽  
Henrik Bohr ◽  
João da Providência
Keyword(s):  
Neutron Stars ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Present Model ◽  
Massive Stars ◽  
Symmetric Nuclear Matter ◽  
The Core ◽  
Meson Coupling

We generalize the Bogoliubov quark-meson coupling (QMC) model to also include hyperons. The hyperon-[Formula: see text]-meson couplings are fixed by the model and the hyperon-[Formula: see text]-meson couplings are fitted to the hyperon potentials in symmetric nuclear matter. The present model predicts neutron stars with masses above 2[Formula: see text] and the radius of a 1.4[Formula: see text] star [Formula: see text]14[Formula: see text]km. In the most massive stars, bags overlap at the core of the star, and this may be interpreted as a transition to deconfined quark matter.

scholarly journals Nuclear equation of state and neutron star cooling

2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Thermal Evolution ◽  
Observation Data ◽  
Nuclear Equation Of State ◽  
The Core ◽  
Dense Nuclear Matter ◽  
Nuclear Models

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.

Quark Clustering and Chiral Symmetry Breaking in Nuclear Matter

2003 ◽  
Vol 18 (32) ◽  
pp. 2255-2264 ◽  
Author(s):  
O. A. Battistel ◽  
G. Krein
Keyword(s):  
Symmetry Breaking ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Chiral Symmetry ◽  
Quark Matter ◽  
Traditional Approach ◽  
Chiral Symmetry Breaking ◽  
Quark Condensate ◽  
Baryon Density ◽  
Hadronic Matter

Chiral symmetry breaking at finite baryon density is usually discussed in the context of quark matter, i.e. a system of deconfined quarks. Many systems like stable nuclei and neutron stars however have quarks confined within nucleons. In this paper we construct a Fermi sea of three-quark nucleon clusters and investigate the change of the quark condensate as a function of baryon density. We study the effect of quark clustering on the in-medium quark condensate and compare results with the traditional approach of modeling hadronic matter in terms of a Fermi sea of deconfined quarks.

DELTA MATTER FORMATION IN DENSE ASYMMETRIC NUCLEAR MEDIUM

2000 ◽  
Vol 15 (24) ◽  
pp. 1529-1537 ◽  
Author(s):  
J. C. T. DE OLIVEIRA ◽  
M. KYOTOKU ◽  
M. CHIAPPARINI ◽  
H. RODRIGUES ◽  
S. B. DUARTE
Keyword(s):  
Nuclear Matter ◽  
Mean Field Theory ◽  
Mean Field ◽  
Symmetric Nuclear Matter ◽  
Coupling Constants ◽  
Nuclear Medium ◽  
Delta Resonance ◽  
Relativistic Mean Field ◽  
Meson Coupling ◽  
Resonance Coupling

In the context of a relativistic mean field theory the delta-resonance matter formation in a highly compressed nuclear medium is investigated. For a given set of nucleon–meson coupling constants, the delta-resonance formation is studied by changing the delta-meson coupling constants. The effect on the equation of state and on the delta-resonance population with respect to changes in the delta-resonance coupling constants values is discussed for very asymmetric and quasi-symmetric nuclear matter, as an extension of works restricted to the symmetric nuclear matter treatment.5,6

NEW ASPECTS ON GRAVITATIONAL WAVE EMISSION BY NEUTRON STARS

2004 ◽  
Vol 13 (07) ◽  
pp. 1293-1296 ◽  
Author(s):  
GUILHERME F. MARRANGHELLO ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
JOSÉ A. de FREITAS PACHECO ◽  
MANFRED DILLIG ◽  
HÉLIO T. COELHO
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Quark Matter ◽  
Inner Core ◽  
Compact Objects ◽  
Wave Emission

We discuss, in this work, new aspects related to the emission of gravitational waves by neutron stars, which undergo a phase transition, from nuclear to quark matter, in its inner core. Such a phase transition would liberate around 1052–53 erg of energy in the form of gravitational waves which, if detected, may shed some light in the structure of these compact objects and provide new insights on the equation of state of nuclear matter.

scholarly journals Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

2018 ◽  
Vol 609 ◽  
pp. A128 ◽  
Author(s):  
Ignazio Bombaci ◽  
Domenico Logoteta
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Symmetric Nuclear Matter ◽  
Heavy Nuclei ◽  
Hartree Fock ◽  
Binary Neutron Star ◽  
Dense Nuclear Matter ◽  
Three Body

Aims. We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods. The EOS is derived using the Brueckner–Bethe–Goldstone quantum many-body theory in the Brueckner–Hartree–Fock approximation. Neutron star properties are next computed solving numerically the Tolman–Oppenheimer–Volkov structure equations. Results. Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to ~4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

scholarly journals Hadron-quark Pasta Phase in Massive Neutron Stars

2021 ◽  
Vol 923 (2) ◽  
pp. 250
Author(s):  
Min Ju ◽  
Jinniu Hu ◽  
Hong Shen
Keyword(s):  
Neutron Stars ◽  
Quark Matter ◽  
Chemical Potential ◽  
Mixed Phase ◽  
Hadronic Matter ◽  
Mean Field Model ◽  
Total Electron ◽  
The Core ◽  
Seitz Cell ◽  
Em Method

Abstract The structured hadron-quark mixed phase, known as the pasta phase, is expected to appear in the core of massive neutron stars. Motivated by the recent advances in astrophysical observations, we explore the possibility of the appearance of quarks inside neutron stars and check its compatibility with current constraints. We investigate the properties of the hadron-quark pasta phases and their influences on the equation of state (EOS) for neutron stars. In this work, we extend the energy minimization (EM) method to describe the hadron-quark pasta phase, where the surface and Coulomb contributions are included in the minimization procedure. By allowing different electron densities in the hadronic and quark matter phases, the total electron chemical potential with the electric potential remains constant, and local β equilibrium is achieved inside the Wigner–Seitz cell. The mixed phase described in the EM method shows the features lying between the Gibbs and Maxwell constructions, which is helpful for understanding the transition from the Gibbs construction to the Maxwell construction with increasing surface tension. We employ the relativistic mean-field model to describe the hadronic matter, while the quark matter is described by the MIT bag model with vector interactions. It is found that the vector interactions among quarks can significantly stiffen the EOS at high densities and help enhance the maximum mass of neutron stars. Other parameters like the bag constant can also affect the deconfinement phase transition in neutron stars. Our results show that hadron-quark pasta phases may appear in the core of massive neutron stars that can be compatible with current observational constraints.

scholarly journals Probing Dense Nuclear Matter in the Laboratory: Experiments at FAIR and NICA

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 171
Author(s):  
Peter Senger
Keyword(s):  
Phase Transition ◽  
Neutron Star ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Heavy Ion Collisions ◽  
Laboratory Experiments ◽  
Heavy Ion ◽  
High Density ◽  
Ion Collisions

The poorly known properties of high-density strongly-interacting matter govern the structure of neutron stars and the dynamics of neutron star mergers. New insight has been and will be gained by astronomical observations, such as the measurement of mass and radius of neutron stars, and the detection of gravitational waves emitted from neutron star mergers. Alternatively, information on the Nuclear Matter Equation-of-State (EOS) and on a possible phase transition from hadronic to quark matter at high baryon densities can be obtained from laboratory experiments investigating heavy-ion collisions. Detector systems dedicated to such experiments are under construction at the “Facility for Antiproton and Ion Research” (FAIR) in Darmstadt, Germany, and at the “Nuclotron-based Ion Collider fAcility” (NICA) in Dubna, Russia. In heavy-ion collisions at these accelerator centers, one expects the creation of baryon densities of up to 10 times saturation density, where quark degrees-of-freedom should emerge. This article reviews the most promising observables in heavy-ion collisions, which are used to probe the high-density EOS and possible phase transition from hadronic to quark matter. Finally, the facilities and the experimental setups will be briefly described.

scholarly journals NICER view on holographic QCD

2022 ◽  
Vol 258 ◽  
pp. 07004
Author(s):  
Niko Jokela
Keyword(s):  
Neutron Stars ◽  
Nuclear Matter ◽  
Strong Coupling ◽  
Quark Matter ◽  
Effective Field ◽  
Field Theories ◽  
Unified Framework ◽  
Holographic Qcd ◽  
Deconfinement Phase Transition ◽  
Matter Phase

The holographic models for dense QCD matter work surprisingly well. A general implication seems that the deconfinement phase transition dictates the maximum mass of neutron stars. The nuclear matter phase turns out to be rather stiff which, if continuously merged with nuclear matter models based on effective field theories, leads to the conclusion that neutron stars do not have quark matter cores in the light of all current astrophysical data. We comment that as the perturbative QCD results are in stark contrast with strong coupling results, any future simulations of neutron star mergers incorporating corrections beyond ideal fluid should proceed cautiously. For this purpose, we provide a model which treats nuclear and quark matter phases in a unified framework at strong coupling.

scholarly journals Massive neutron stars with holographic multiquark cores

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
Sitthichai Pinkanjanarod ◽  
Piyabut Burikham
Keyword(s):  
Neutron Stars ◽  
Nuclear Matter ◽  
Quark Matter ◽  
Bound States ◽  
Theoretical Calculations ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Nucl Phys ◽  
Density Region ◽  
Link Type

AbstractPhases of nuclear matter are crucial in the determination of physical properties of neutron stars (NS). In the core of NS, the density and pressure become so large that the nuclear matter possibly undergoes phase transition into a deconfined phase, consisting of quarks and gluons and their colour bound states. Even though the quark-gluon plasma has been observed in ultra-relativistic heavy-ion collisions (Gyulassy and McLerran, Nucl Phys A 750:30–63, 2005; Andronic et al., Nature 561: 321–330, 2018), it is still unclear whether exotic quark matter exists inside neutron stars. Recent results from the combination of various perturbative theoretical calculations with astronomical observations (Demorest et al., Nature 467:1081–1083, 2010; Antoniadis et al., Science 340:1233232, 2013) shows that (exotic) quark matter could exist inside the cores of neutron stars above 2.0 solar masses ($$M_{\odot }$$ M ⊙ ) (Annala et al., Nat Phys, 10.1038/s41567-020-0914-9, arXiv:1903.09121 [astro-ph.HE], 2020). We revisit the holographic model in Refs. (Burikham et al., JHEP 05:006, arXiv:0811.0243 [hep-ph], 2009; Burikham et al., JHEP 06:040, arXiv:1003.5470 [hep-ph], 2010) and implement the equation of states (EoS) of multiquark nuclear matter to interpolate the pQCD EoS in the high-density region with the nuclear EoS known at low densities. For sufficiently large energy density scale ($$\epsilon _{s}$$ ϵ s ) of the model, it is found that multiquark phase is thermodynamically prefered than the stiff nuclear matter above the transition points. The NS with holographic multiquark core could have masses in the range $$1.96{-}2.23~(1.64{-}2.10) M_{\odot }$$ 1.96 - 2.23 ( 1.64 - 2.10 ) M ⊙ and radii $$14.3{-}11.8~(14.0{-}11.1)$$ 14.3 - 11.8 ( 14.0 - 11.1 ) km for $$\epsilon _{s}=26~(28)$$ ϵ s = 26 ( 28 ) GeV/fm$$^{3}$$ 3 respectively. Effects of proton–baryon fractions are studied for certain type of baryonic EoS; larger proton fractions could reduce radius of the NS with multiquark core by less than a kilometer.

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