Quark matter in light neutron stars

Ferreira, Márcio; Pereira, Renan Câmara; Providência, Constança

doi:10.1103/physrevd.102.083030

Cited by 37 publications

(41 citation statements)

References 72 publications

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“…7), astronomical observations can also be used to place constraints on the relevant parameter space. In general, since GW170817 provided an upper limit onΛ, any physical effect that results in a softening of the equation of state can be consistent with the data [88,[240][241][242][243][244][245][246] As such, a strong first-order phase transition might make an equation of state model compatible with the GW170817 data, even if the hadronic part on its own is not [152,[247][248][249][250]. A number of studies have constructed models that can successfully interpret the inspiral signal from GW170817 as the coalescence of any combination of hadronic and hybrid hadronic-quark neutron stars and place corresponding constraints on the relevant model parameter space [149,247,248,[251][252][253][254][255][256][257][258][259][260].…”

Section: Microscopic Propertiesmentioning

confidence: 85%

Neutron-star tidal deformability and equation-of-state constraints

2020

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Despite their long history and astrophysical importance, some of the key properties of neutron stars are still uncertain. The extreme conditions encountered in their interiors, involving matter of uncertain composition at extreme density and isospin asymmetry, uniquely determine the stars' macroscopic properties within General Relativity. Astrophysical constraints on those macroscopic properties, such as neutron star masses and radii, have long been used to understand the microscopic properties of the matter that forms them. In this article we discuss another astrophysically observable macroscopic property of neutron stars that can be used to study their interiors: their tidal deformation. Neutron stars, much like any other extended object with structure, are tidally deformed when under the influence of an external tidal field. In the context of coalescences of neutron stars observed through their gravitational wave emission, this deformation, quantified through a parameter termed the tidal deformability, can be measured. We discuss the role of the tidal deformability in observations of coalescing neutron stars with gravitational waves and how it can be used to probe the internal structure of Nature's most compact matter objects. Perhaps inevitably, a large portion of the discussion will be dictated by GW170817, the most informative confirmed detection of a binary neutron star coalescence with gravitational waves as of the time of writing.

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Section: Microscopic Propertiesmentioning

confidence: 85%

Neutron-star tidal deformability and equation-of-state constraints

2020

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“…In our previous works [49,50], we have analyzed hybrid stars using the NJL model with different interaction terms at the Lagrangian level which describes the quark phase. The usual three-flavor NJL model [20,51] with additional vector and pseudovector interactions and the vector-isovector and pseudovector-isovector interactions were explored in [49].…”

Section: Introductionmentioning

confidence: 99%

“…It was shown that considerable quark core sizes would require moderate values for the quark vector-isoscalar term and a weak vector isovector term. Additional higher-order repulsive interactions, four-quark and eight-quark vector-isoscalar interactions, were included in [50]. The eight-quark vector-isoscalar channel was shown to allow for the appearance of a quark core at moderately low NS masses, ∼1 M ⊙ , while providing the required repulsion to keep the star stability up to ∼2.1 M ⊙ .…”

Section: Introductionmentioning

confidence: 99%

“…The eight-quark vector-isoscalar channel was shown to allow for the appearance of a quark core at moderately low NS masses, ∼1 M ⊙ , while providing the required repulsion to keep the star stability up to ∼2.1 M ⊙ . It was also shown that both the heaviest NS mass and radius are sensitive to the strength of an eight-quark vectorisoscalar channel [50].…”

Section: Introductionmentioning

confidence: 99%

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Hybrid stars with large strange quark cores constrained by GW170817

2021

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We analyze the impact of several multiquark interaction channels on the properties of hybrid stars. Four and eight vector interactions were included in the SUð3Þ Nambu-Jona-Lasinio model to describe the quark matter, and all vectorlike interactions were investigated. The hybrid stars were built starting from an hadronic equation of state that satisfy presently accepted nuclear matter properties and considering the quark model constrained by the vacuum properties of several light mesons. The interplay between the eight-quark vector interaction and the four-quark isovector-vector interaction determine the size of the quark core and its strangeness content. The inclusion of a isovector-vector interaction is essential to obtain large s-quark contents and a smaller central speed of sound, although this interaction pushes the onset of quarks to larger densities. It is observed that low mass stars, with a mass below 1.4 M ⊙ , may contain a quark core but with a small strangeness content. It is shown that the presently existing mass and tidal deformability constraints from neutron stars observations allow for the existence of hybrid stars with a large strangeness content and large quark cores for binary mass ratios q ¼ M 2 =M 1 ≳ 0.85.

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“…Indeed, even if the exact location of the deconfinement transition towards quark matter is essentially unknown, if strange quark matter is not absolutely stable such a transition is expected at high density [18]. In particular, if this transition is strongly first order, the parameter space of the EoS increases, leading to a much larger spread of the possible M(R) relation ( [19] and references therein). Because of the phenomenological nature of the effective models used for the quark phase, settling the parameter space associated to a phase transition to quark matter is a very hard task.…”

Section: Modelling the Neutron-star Equation Of Statementioning

confidence: 99%