The Hyperon Puzzle in Neutron Stars

Bombaci, Ignazio

doi:10.7566/jpscp.17.101002

Cited by 32 publications

(21 citation statements)

References 78 publications

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“…The situation is even worse for the hyperonnucleon and hyperon-hyperon interactions, for which lot of work still needs to be done. This is ultimately related to the "hyperon-puzzle" in neutron stars [5], which will be discussed below.…”

Section: Basic Knowledge Of Naturementioning

confidence: 99%

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Grand Challenges in Nuclear Physics: A Long and Exciting Way to Go

Marcucci

2018

Front. Phys.

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Section: Basic Knowledge Of Naturementioning

confidence: 99%

“…All these issues represent grand challenges in NP. Last, but not least, a long-lasting puzzle which needs to be solved in the next years is the so-called "hyperon-puzzle" [5]. The composition of matter at the supra-saturation densities reached in neutron star cores is very uncertain.…”

Section: Nuclear Physics At Service For Other Fieldsmentioning

confidence: 99%

Grand Challenges in Nuclear Physics: A Long and Exciting Way to Go

Marcucci

2018

Front. Phys.

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“…This difficulty to reconcile the measured masses of neutron stars with the seemingly unavoidable presence of hyperons in their interiors is called hyperon puzzle (Lonardoni et al 2015;Bombaci 2017;Chatterjee & Vidaña 2016) in neutron stars. This unsolved puzzle is currently the subject of several investigations, and various possible solutions have been proposed.…”

Section: Neutron Star Structurementioning

confidence: 99%

Neutron star properties from optimised chiral nuclear interactions

Logoteta¹,

Bombaci

2018

Publ. Astron. Soc. Aust.

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We adopt two-and three-body nuclear forces derived at the next-to-next-to-leading-order (N2LO) in the framework of effective chiral perturbation theory (ChPT) to calculate the equation of state (EOS) of β-stable neutron star matter using the Brueckner-Hartree-Fock many-body approach. We use the recent optimized chiral two-body nuclear interaction at N2LO derived by Ekström et al. (2014) and two different parametrizations of the three-body N2LO interaction: the first one is fixed to reproduce the saturation point of symmetric nuclear matter while the second one is fixed to reproduce the binding energies of light atomic nuclei. We show that in the second case the properties of nuclear matter are not well determined whereas in the first case various empirical nuclear matter properties around the saturation density are well reproduced. We also calculate the nuclear symmetry energy E sym as a function of the nucleonic density and compare our results with the empirical constraints obtained using the excitation energies of isobaric analog states in nuclei and the experimental data on the neutron skin thickness of heavy nuclei. We next calculate various neutron star properties and in particular the mass-radius and mass-central density relations. We find that the adopted interactions based on a fully microscopic framework, are able to provide an EOS which is consistent with the present data of measured neutron star masses and in particular with the mass M = 2.01 ± 0.04M ⊙ of the neutron star in PSR J0348+0432. We finally consider the possible presence of hyperons in the stellar core and we find a softening of the EOS and a substantial reduction of the stellar maximum mass in agreement with similar calculations present in the literature.

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“…The naive extrapolation of two body interaction fitted to hypernuclear data leads to Λ hyperon condensation at 2 ∼ 3 times nuclear matter density in neutron stars, which leads to maximum neutron star mass of less than 1.5 M ⊙ [13]. On the other hand the recently observed neutron stars J1614-2230 [14] and J0348-0432 [15] have observed masses of ð1.97 AE 0.04ÞM ⊙ and ð2.01 AE 0.04ÞM ⊙ respectively.…”

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confidence: 99%

Tribaryon configurations and the inevitable three nucleon repulsions at short distance

Park

Lee

2018

Phys. Rev. D

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We decompose the tribaryon configuration in terms of SU (3) flavor and spin state and analyze their color-spin-flavor wave function following the Pauli principle. By comparing the color-color and color-spin interactions of compact tribaryon configuration against the lowest three nucleon threshold within a constituent quark model, we show that the three nucleon configurations have to be repulsive at short distance for all possible quantum numbers and all values of the SU(3) symmetry breaking parameter. Our work identifies the origin of the repulsive nuclear three body forces including the hyperons at short distance that are called for from phenomenological considerations starting from nuclear matter to the maximum mass of a neutron star. DOI: 10.1103/PhysRevD.98.034001 The importance of three nucleon force was discussed from the early days of nuclear physics [1,2] to address nuclear configurations beyond the deuteron [3][4][5]. Phenomenologically, the long distance part of the three nuclear force is obtained using the pion mediated interactions [6,7] which gives the additional attraction necessary to fit the experimental 3 H binding energy. However, as one tries to go beyond the few body system and understand the saturation properties of nuclear matter [6,8] and the compressibility consistent with experiments [9], it becomes clear that the three body nuclear force including those involving hyperons [10] are repulsive at short distance.Recently, there is a renewed interest in the three body nuclear force as there are compelling evidences that the force should be repulsive at short distance from analyzing the extrapolated dense nuclear matter equation of state (EOS) in the neutron stars [11,12]. The naive extrapolation of two body interaction fitted to hypernuclear data leads to Λ hyperon condensation at 2 ∼ 3 times nuclear matter density in neutron stars, which leads to maximum neutron star mass of less than 1.5 M ⊙ [13]. On the other hand the recently observed neutron stars J1614-2230 [14] and J0348-0432 [15] have observed masses of ð1.97 AE 0.04ÞM ⊙ and ð2.01 AE 0.04ÞM ⊙ respectively. A natural way to solve the "hyperon puzzle" is to introduce a repulsive short distance three body force including the hyperon which becomes more important at high density and naturally leads to a stiffer equation of state and forces the hyperons to appear at a much higher density [16].In this work, we will show why the short distance part of the three nucleon interaction, including the hyperons, should be repulsive. Our calculation is based on Pauli principle and the color-color and color-spin interaction for a decomposed color-flavor-spin wave function with broken flavor SU(3). Specifically, we compare the stability of the compact tribaryon configuration against three nucleon configuration of the lowest threshold within a constituent quark picture for all possible quantum numbers. We find that for every quantum number, the tribaryon configuration is highly repulsive compared to the lowest three nucleon threshold even in the SU(...

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The Hyperon Puzzle in Neutron Stars

Cited by 32 publications

References 78 publications

Grand Challenges in Nuclear Physics: A Long and Exciting Way to Go

Grand Challenges in Nuclear Physics: A Long and Exciting Way to Go

Neutron star properties from optimised chiral nuclear interactions

Tribaryon configurations and the inevitable three nucleon repulsions at short distance

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