Impact of NICER's Radius Measurement of PSR J0740+6620 on Nuclear Symmetry Energy at Suprasaturation Densities

Zhang, Nai-Bo; Li, Bao-An

doi:10.48550/arxiv.2105.11031

Cited by 7 publications

(7 citation statements)

References 51 publications

(80 reference statements)

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“…The lower bound on the radius of PSR J0740 constrains a highly relevant region of the mass-radius (M-R) diagram of compact stars (CS), which in combination with the determination of the tidal deformability (TD) of a star of mass ∼ 1.4M in the GW170817 event by the LIGO-Virgo Collaboration (Abbott et al 2019) put significant constraints on the EoS of CS. These require that the stellar EoS must be moderately soft at intermediate densities (to allow for relatively small TDs) and must be stiff enough at high densities (to allow for two-solar mass CSs) [see (Tan et al 2021;Biswas 2021;Legred et al 2021;Raaijmakers et al 2021;Huth et al 2021;Zhang & Li 2021;Tang et al 2021)]. Recently, the Lead Radius Experiment Collaboration (PREX-II) reported the most precise measurement yet of the neutron skin thickness of a heavy nucleus (Adhikari et al 2021), a quantity strongly correlated with the slope of nuclear symmetric energy L sym at saturation density (ρ sat ), which constrains the nuclear EoS at densities ≥ ρ sat .…”

Section: Introductionmentioning

confidence: 99%

Relativistic hybrid stars in light of the NICER PSR J0740+6620 radius measurement

Li,

Sedrakian,

Alford

2021

Preprint

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We explored the implications of the recent radius determination of PSR J0740+6620 by the NICER experiment combined with the neutron skin measurement by PREX-II experiment for the structure of hybrid stars with a strong first-order phase transition from nucleonic to quark matter. We combine a covariant density-functional nucleonic equation of state (EoS) with a constant speed of sound EoS for quark matter. We show that the radius and tidal deformability ranges obtained from GW170817 can be reconciled with the PREX-II results if there is a phase transition to quark matter in the low-mass compact star. In the high-mass segment, the EoS needs to be stiff to comply with the large-radius inference for PSR J0740+6620 and J0030+0451 with a masses M 2M and M 1.4M . We show that twin stars are not excluded, but the mass and radius ranges (with M ≥ M ) are restricted to narrow domains ∆M twin 0.05M and ∆R twin ∼ 1.0 km. We also show that the existence of twin configurations is compatible with the light companion in GW190814 event being a hybrid star in the case of values of the sound-speed square s 0.6.

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Section: Introductionmentioning

confidence: 99%

Relativistic hybrid stars in light of the NICER PSR J0740+6620 radius measurement

Li,

Sedrakian,

Alford

2021

Preprint

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“…A inferior bound of 11.4 km, 12.2 km, 11.6 km and 12.2 km was found respectively in ref. [27,39,51,52]. An average value of 11.85 km arises and I also use this value as a constraint to the EoS.…”

Section: Astrophysical Results and Constraintsmentioning

confidence: 99%

Hyperonic neutron stars: reconciliation between nuclear properties and NICER and LIGO/VIRGO results

Lopes

2021

Preprint

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Using a extended version of the Quantum Hadrodynamics (QHD), I propose a new microscopic equation of state (EoS) able to correctly reproduce the main properties of symmetric nuclear matter at the saturation density, as well produce massive neutron stars and satisfactory results for the radius and the tidal parameter Λ. I show that even when hyperons are present, this EoS is able to reproduce at least 2.00 solar masses neutron star. The constraints about the radius of a 2.00M⊙ and the minimum mass that enable direct Urca effect are also checked.

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“…For simplicity, we did not include the contributions from antibaryons in Eqs. ( 30)- (32) (although this can be readily done following Ref. [24]).…”

Section: The Modelmentioning

confidence: 99%

Effects of chiral symmetry restoration on meson and dilepton production in relativistic heavy-ion collisions

Larionov,

von Smekal

2021

Preprint

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We include effects of chiral symmetry and its restoration in the kinetic equations for baryon propagation and explore the consequences for η, π 0 , ρ and dilepton production in heavy-ion collisions at 1-2A GeV. Numerical calculations are performed using the GiBUU microscopic transport model supplemented by the parity-doublet model for the mean fields of the nucleon and the N * (1535) resonance. In this chiral model, a strong dropping of the Dirac mass of the N * (1535) in the highdensity stage of a collision leads to a considerable enhancement in the production of this resonance as compared to the standard (non-linear) Walecka model. As the system expands, the Dirac masses of these abundant soft N * (1535) resonances gradually increase and ultimately cross the N η decay threshold. As a result, an enhanced low-energy η production is observed in the calculations with chiral mean fields. Comparing with TAPS data on η and π 0 production we find that the chiral model improves the agreement for the m t -spectra of η's at small m t in heavy colliding systems.A similar enhancement is also observed in the soft ρ production due to chiral symmetry and its partial restoration. The resulting dilepton yields at low and intermediate invariant masses are slightly enhanced due to these chiral effects which further improve the agreement between GiBUU transport simulations and HADES data for C+C at 1A GeV.

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Impact of NICER's Radius Measurement of PSR J0740+6620 on Nuclear Symmetry Energy at Suprasaturation Densities

Cited by 7 publications

References 51 publications

Relativistic hybrid stars in light of the NICER PSR J0740+6620 radius measurement

Relativistic hybrid stars in light of the NICER PSR J0740+6620 radius measurement

Hyperonic neutron stars: reconciliation between nuclear properties and NICER and LIGO/VIRGO results

Effects of chiral symmetry restoration on meson and dilepton production in relativistic heavy-ion collisions

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