Delta baryons and diquark formation in the cores of neutron stars

Malfatti, Germán; Orsaria, M.; Ranea‐Sandoval, Ignacio F.; Contrera, Gustavo A.; Weber, Fridolin

doi:10.1103/physrevd.102.063008

Cited by 53 publications

(60 citation statements)

References 98 publications

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“…Moreover, it is argued that GW170817 data also imply a general upper limit of about 2.3M for the mass of a cold spherical NS [221]. These constraints have been taken into account for the analysis of EoS arising from hybrid star models that include nlNJL approaches for quark matter [222][223][224][225][226][227][228].…”

Section: Astrophysical Applicationsmentioning

confidence: 99%

“…Even in the case in which the model parameters are compatible with a quark matter core at T = 0, this deconfined phase region would disappear for hot neutron or proto-neutron stars. In a more recent work [228], the analysis is extended (at T = 0) to a three-flavor nlNJL model that includes also a 2SC+s superconducting phase. Depending on the stability criteria for the hadron-quark interface, once again it is found that the existence of neutron stars with a superconducting quark matter core can be compatible with observational data.…”

Section: Astrophysical Applicationsmentioning

confidence: 99%

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Strong-Interaction Matter under Extreme Conditions from Chiral Quark Models with Nonlocal Separable Interactions

2021

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We review the current status of the research on effective nonlocal NJL-like chiral quark models with separable interactions, focusing on the application of this approach to the description of the properties of hadronic and quark matter under extreme conditions. The analysis includes the predictions for various hadron properties in vacuum, as well as the study of the features of deconfinement and chiral restoration phase transitions for systems at finite temperature and/or density. We also address other related subjects, such as the study of phase transitions for imaginary chemical potentials, the possible existence of inhomogeneous phase regions, the presence of color superconductivity, the effects produced by strong external magnetic fields and the application to the description of compact stellar objects.

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Section: Astrophysical Applicationsmentioning

confidence: 99%

Section: Astrophysical Applicationsmentioning

confidence: 99%

Strong-Interaction Matter under Extreme Conditions from Chiral Quark Models with Nonlocal Separable Interactions

2021

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“…To describe hadronic matter in the outer core of HSs we use the SW4L parametrization of the density dependent non-linear relativistic mean-field model [52][53][54]. This family of models have gained popularity since the density-dependent couplings allows one to account for the latest slope values of the symmetry energy consistent with experimental data [55,56].…”

Section: The Hadronic Phasementioning

confidence: 99%

“…These values are adjusted to the properties of nuclear matter at saturation density shown in Table 2 (for details, see Ref. [54], and references therein).…”

Section: The Hadronic Phasementioning

confidence: 99%

Hybrid Stars with Color Superconducting Cores in an Extended FCM Model

et al. 2021

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We investigate the influence of repulsive vector interactions and color superconductivity on the structure of neutron stars using an extended version of the field correlator method (FCM) for the description of quark matter. The hybrid equation of state is constructed using the Maxwell description, which assumes a sharp hadron-quark phase transition. The equation of state of hadronic matter is computed for a density-dependent relativistic lagrangian treated in the mean-field approximation, with parameters given by the SW4L nuclear model. This model described the interactions among baryons in terms of σ,ω,ρ,σ*, and ϕ mesons. Quark matter is assumed to be in either the CFL or the 2SC+s color superconducting phase. The possibility of sequential (hadron-quark, quark-quark) transitions in ultra-dense matter is investigated. Observed data related to massive pulsars, gravitational-wave events, and NICER are used to constrain the parameters of the extended FCM model. The successful equations of state are used to explore the mass-radius relationship, radii, and tidal deformabilities of hybrid stars. A special focus lies on investigating consequences that slow or fast conversions of quark-hadron matter have on the stability and the mass-radius relationship of hybrid stars. We find that if slow conversion should occur, a new branch of stable massive stars would exist whose members have radii that are up to 1.5 km smaller than those of conventional neutron stars of the same mass. Such objects could be possible candidates for the stellar high-mass object of the GW190425 binary system.

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“…which is given in terms of the bare baryon mass m B , the density-dependent coupling g B (n), and the mean-field solution of the -meson field equation that follows from the Lagrangian shown in Equation ( 1) (for details, see Malfatti et al, 2020;Spinella & Weber, 2020;Weber, 1999). The quantity * B in Equation ( 11) stands for the effective chemical potential of a baryon of type B.…”

Section: The Density-dependent Relativistic Mean-field (Rmf) Model Dd2mentioning

confidence: 99%

Gravitational radiation‐reaction driven instabilities in rotating neutron stars

et al. 2021

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We investigate in this work two different types of instabilities that set limits on the rotation rates of neutron (compact) stars. The first one is that caused by rotation at the Kepler frequency, at which mass shedding at the star's equator sets in. The second limit is set by instabilities driven by the growth of gravitational radiation-reaction (GRR) driven f -modes of order m (= 2, 3, … ), which are moderated by shear and bulk viscosity. The calculations are performed for two relativistic models for the nuclear equation of state, DD2 and ACB4. The latter accounts for a phase transition that gives rise to the existence of so-called mass-twin compact stars. Our results confirm that the stable rotation periods of cold neutron stars are determined by the m = 2 modes and that these modes are excited at rotation periods between 1 and 1.4 ms (20-30% above the Kepler periods of these stars). The situation is reversed in hot neutron stars where bulk viscosity damps the GRR modes, pushing the excitation period of the f -mode instability to values below the Kepler period. For cold mass-twin compact stars, we find that the m = 2 instability sets in at rotation periods between 0.8 and 1 ms (25-30% below the Kepler period). This feature may allow one to distinguish conventional neutron stars from their possibly existing mass-twin counterparts observationally, provided the f -mode instability, which is expected to compete with the r-mode instability, sets the limit on stable rotation of compact stars.

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Delta baryons and diquark formation in the cores of neutron stars

Cited by 53 publications

References 98 publications

Strong-Interaction Matter under Extreme Conditions from Chiral Quark Models with Nonlocal Separable Interactions

Strong-Interaction Matter under Extreme Conditions from Chiral Quark Models with Nonlocal Separable Interactions

Hybrid Stars with Color Superconducting Cores in an Extended FCM Model

Gravitational radiation‐reaction driven instabilities in rotating neutron stars

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