Neutrino emissivity in the quark-hadron mixed phase of neutron stars

In the first part of this paper, we investigate the possible existence of a structured hadron-quark mixed phase in the cores of neutron stars. This phase, referred to as the hadron-quark pasta phase, consists of spherical blob, rod, and slab rare phase geometries. Particular emphasis is given to modeling the size of this phase in rotating neutron stars. We use the relativistic mean-field theory to model hadronic matter and the non-local three-flavor Nambu-Jona-Lasinio model to describe quark matter. Based on these models, the hadron-quark pasta phase exists only in very massive neutron stars, whose rotational frequencies are less than around 300 Hz. All other stars are not dense enough to trigger quark deconfinement in their cores. Part two of the paper deals with the quark-hadron composition of hot (proto) neutron star matter. To this end we use a local three-flavor Polyakov-Nambu-Jona-Lasinio model which includes the 't Hooft (quark flavor mixing) term. It is found that this term leads to non-negligible changes in the particle composition of (proto) neutron stars made of hadron-quark matter.

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“…lattice in the core of a neutron star and the neutrino emissivity in this phase have been investigated in Refs. [32,[34][35][36]].…”

Section: Pasta Structure Of the Hadron-quark Phasementioning

confidence: 99%

Phases of Hadron-Quark Matter in (Proto) Neutron Stars

et al. 2019

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“…Hadronic matter is modeled in the framework of the relativistic nonlinear mean-field (RMF) approach [23,24], which describes baryons interacting through the exchange of scalar, vector, and isovector mesons (for details, see [6,7,25]). The RMF approach is parametrized to reproduce the following properties of symmetric nuclear matter at saturation density n 0 (see Table 1): the binding energy per nucleon (E 0 ), the nuclear incompressibility (K 0 ), the isospin asymmetry energy (J), and the effective mass (m * /m N ).…”

Section: Improved Set Of Models For the Nuclear Equation Of Statementioning

confidence: 99%

Neutrino Emissivity in the Quark-Hadron Mixed Phase

et al. 2018

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Abstract:In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the cores of neutron stars. To this end we use relativistic mean-field equations of state to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron mixed phase and its crystalline structure using the Glendenning construction, allowing for the formation of spherical blob, rod, and slab rare phase geometries. Finally, we calculate the neutrino emissivity due to electron-lattice interactions utilizing the formalism developed for the analogous process in neutron star crusts. We find that the contribution to the neutrino emissivity due to the presence of a crystalline quark-hadron mixed phase is substantial compared to other mechanisms at fairly low temperatures ( < ∼ 10 9 K) and quark fractions ( < ∼ 30%), and that contributions due to lattice vibrations are insignificant compared to static-lattice contributions. There are a number of open issues that need to be addressed in a future study on the neutrino emission rates caused by electron-quark blob bremsstrahlung. Chiefly among them are the role of collective oscillations of matter, electron band structures, and of gaps at the boundaries of the Brillouin zones on bremsstrahlung, as discussed in the summary section of this paper. We hope this paper will stimulate studies addressing these issues.

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“…If one uses alternative constructions mixed phases will appear, which we do not discuss here (see Refs. [28,52]). We will assume that strange quarks because of their large mass are not important at the densities relevant to our models.…”

Section: Equilibrium Structure Of Hybrid Starsmentioning

confidence: 99%

Cooling compact stars and phase transitions in dense QCD

Sedrakian

2016

Eur. Phys. J. A

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We report new simulations of cooling of compact stars containing quark cores and updated fits to the Cas A fast cooling data. Our model is built on the assumption that the transient behaviour of the star in Cas A is due to a phase transition within the dense QCD matter in the core of the star. Specifically, the fast cooling is attributed to an enhancement in the neutrino emission triggered by a transition from a fully gapped, two-flavor, red-green colorsuperconducting quark condensate to a superconducting crystalline or an alternative gapless, color-superconducting phase. The blue colored condensate is modeled as a Bardeen-Cooper-Schrieffer (BCS)-type color superconductor with spin-one pairing order parameter. We study the sensitivity of the fits to the phase transition temperature, the pairing gap of blue quarks and the time-scale characterizing the phase transition (the latter modelled in terms of a width parameter). Relative variations in these parameter around their best fit values larger than 10 −3 spoil the fit to the data. We confirm the previous finding that the cooling curves show significant variations as a function of compact star mass, which allows one to account for dispersion in the data on the surface temperatures of thermally emitting neutron stars. PACS. 97.60.Jd Neutron stars -26.60.-c Nuclear matter aspects of neutron stars -95.30.Cq Elementary particle processes -74.25.Dw Superconductivity phase diagrams

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Neutrino emissivity in the quark-hadron mixed phase of neutron stars

Cited by 27 publications

References 62 publications

Phases of Hadron-Quark Matter in (Proto) Neutron Stars

Phases of Hadron-Quark Matter in (Proto) Neutron Stars

Neutrino Emissivity in the Quark-Hadron Mixed Phase

Cooling compact stars and phase transitions in dense QCD

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