Nonlocal PNJL models and quark matter in compact stars

Blaschke, D.; Alvarez-Castillo, David; Benić, Sanjin; Contrera, Gustavo A.; Łastowiecki, R.

doi:10.22323/1.171.0249

Cited by 36 publications

(56 citation statements)

References 33 publications

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“…Fukushima & Sasaki 2013;Fukushima 2014). Since increasing the isospin asymmetry would result in lowering the temperature of the CEP to zero (Ohnishi et al 2011) the detection of first-order phase transition signals in zero temperature asymmetric compact star matter like the mass twin phenomenon would thus prove the existence of at least one CEP in the QCD phase diagram Alvarez-Castillo & Blaschke (2013), Blaschke et al (2013a). Unfortunately, heavy-ion collision experiments probe matter with only slight isospin asymmetry of about 60% neutron excess and hence cannot provide constraints for larger isospin asymmetry or even β-equilibrium (>90 % neutron excess) relevant for compact star phenomenology.…”

Section: Introductionmentioning

confidence: 98%

A new quark-hadron hybrid equation of state for astrophysics

Benić

Blaschke

Alvarez-Castillo

et al. 2015

A&A

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263

288

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Aims. We present a new microscopic hadron-quark hybrid equation of state model for astrophysical applications, from which compact hybrid star configurations are constructed. These are composed of a quark core and a hadronic shell with a first-order phase transition at their interface. The resulting mass-radius relations are in accordance with the latest astrophysical constraints. Methods. The quark matter description is based on a quantum chromodynamics (QCD) motivated chiral approach with higher-order quark interactions in the Dirac scalar and vector coupling channels. For hadronic matter we select a relativistic mean-field equation of state with density-dependent couplings. Since the nucleons are treated in the quasi-particle framework, an excluded volume correction has been included for the nuclear equation of state at suprasaturation density which takes into account the finite size of the nucleons. Results. These novel aspects, excluded volume in the hadronic phase and the higher-order repulsive interactions in the quark phase, lead to a strong first-order phase transition with large latent heat, i.e. the energy-density jump at the phase transition, which fulfils a criterion for a disconnected third-family branch of compact stars in the mass-radius relationship. These twin stars appear at high masses (∼2 M ) that are relevant for current observations of high-mass pulsars.Conclusions. This analysis offers a unique possibility by radius observations of compact stars to probe the QCD phase diagram at zero temperature and large chemical potential and even to support the existence of a critical point in the QCD phase diagram.

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Section: Introductionmentioning

confidence: 98%

A new quark-hadron hybrid equation of state for astrophysics

Benić

Blaschke

Alvarez-Castillo

et al. 2015

A&A

Self Cite

263

288

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“…On the other hand, if the canonical 1.4M has a radius larger than about 14km, it implies that the hadronic equation of state is stiff at large densities and even the maximum mass configuration could be composed by just nucleon because its central density is smaller than the thresholds of hyperons and deltas. A phase transition to quark matter could still occur at large densities, as proposed in [59], leading to a third family branch of hybrid stars with masses close to 2M . Testing this scenario, which is very much different with respect to ours, would require precise measurements of the radii of the most massive stars.…”

Section: Icnfp 2014mentioning

confidence: 86%

Delta isobars in neutron stars

Pagliara

Drago

Lavagno

et al. 2015

EPJ Web of Conferences

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Abstract. The appearance of delta isobars in beta-stable matter is regulated by the behaviour of the symmetry energy at densities larger than saturation density. We show that by taking into account recent constraints on the density derivative of the symmetry energy and the theoretical and experimental results on the excitations of delta isobars in nuclei, delta isobars are necessary ingredients for the equations of state used for studying neutron stars. We analyze the effect of the appearance of deltas on the structure of neutron stars: as in the case of hyperons, matter containing delta is too soft for allowing the existence of 2M neutron stars. Quark stars on the other hand, could reach very massive configurations and they could form from a process of conversion of hadronic stars in which an initial seed of strangeness appears through hyperons.

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“…This third family of CS is observationally detectable (in principle) by simultaneous mass and radius measurement with sufficient accuracy whereby the high masses should be about the same, such as for the two known high-mass pulsars PSR J1614-2230 [4] and PSR J0348+0432 [5] but the radii should differ, resulting in the "mass twin" phenomenon [37,38,39,40]. Also shown are previous models which could obtain the high mass twin phenomenon, see [12] for comparison. In the left panel of Fig.…”

Section: Advanced Njl Model For High-density Quark Mattermentioning

confidence: 99%

“…The answer is positive and leads to the characteristic feature of high-mass twin stars, see also [11,12]. In the following two sections we shall discuss the EVA and the density-dependent stiffening of quark matter in an advanced Nambu-Jona-Lasinio (NJL) model, respectively, both being the main ingredients to this new class of EoS for CS to be summarized in the subsequent section.…”

Section: Introductionmentioning

confidence: 99%

High-mass twins & resolution of the reconfinement, masquerade and hyperon puzzles of compact star interiors

Blaschke

Alvarez-Castillo

2016

AIP Conference Proceedings

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Abstract. We aim at contributing to the resolution of three of the fundamental puzzles related to the still unsolved problem of the structure of the dense core of compact stars (CS): (i) the hyperon puzzle: how to reconcile pulsar masses of 2 M with the hyperon softening of the equation of state (EoS); (ii) the masquerade problem: modern EoS for cold, high density hadronic and quark matter are almost identical; and (iii) the reconfinement puzzle: what to do when after a deconfinement transition the hadronic EoS becomes favorable again? We show that taking into account the compositeness of baryons (by excluded volume and/or quark Pauli blocking) on the hadronic side and confining and stiffening effects on the quark matter side results in an early phase transition to quark matter with sufficient stiffening at high densities which removes all three present-day puzzles of CS interiors. Moreover, in this new class of EoS for hybrid CS falls the interesting case of a strong first order phase transition which results in the observable high mass twin star phenomenon, an astrophysical observation of a critical endpoint in the QCD phase diagram.

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Nonlocal PNJL models and quark matter in compact stars

Cited by 36 publications

References 33 publications

A new quark-hadron hybrid equation of state for astrophysics

A new quark-hadron hybrid equation of state for astrophysics

Delta isobars in neutron stars

High-mass twins & resolution of the reconfinement, masquerade and hyperon puzzles of compact star interiors

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