Hyperon Puzzle: Hints from Quantum Monte Carlo Calculations

Lonardoni, Diego; Lovato, Alessandro; Gandolfi, Stefano; Pederiva, Francesco

doi:10.1103/physrevlett.114.092301

Cited by 281 publications

(329 citation statements)

References 64 publications

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“…The masses of NSs with the abovementioned four hyperon interactions are smaller than those for pure nucleon matter at ρ m higher than the critical mass density ρ c = 7.4 × 10 14 g/cm 3 (vertical dotted line), i.e., hyperons appear in NS matter at ρ m ≥ ρ c . This result shows that the hyperon mixing reduces the NS mass, as reported in the studies based on other many-body techniques [3][4][5]. Figure 1 also shows that the NS mass increases monotonically as the odd-state component of the ΛΛ interaction becomes more repulsive, i.e., from Type 1 to 4.…”

Section: Numerical Results and Discussionsupporting

confidence: 72%

“…In particular, these heavy NSs are difficult to explain when hyperon mixing in NSs is considered. To investigate the hyperon mixing, some EOSs of nuclear matter including hyperons are constructed based on the microscopic many-body calculations starting from the bare baryon interactions [3][4][5]. However, uncertainties in hyperon-nucleon (Y N) and hyperon-hyperon (YY) interactions are large, as compared with the nucleon-nucleon (NN) interaction.…”

Section: Introductionmentioning

confidence: 99%

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Variational Approach to Neutron Star Matter with Hyperons

Togashi¹,

Hiyama²,

Yamamoto³

et al. 2017

Proceedings of the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015)

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Equations of state (EOSs) for uniform nuclear matter including Λ and Σ − hyperons are constructed with the variational method starting from the bare baryon interactions to study the structure and composition of neutron stars (NSs). For the nucleon sector, the Argonne v18 two-nucleon potential and the Urbana IX three-nucleon potential are adopted. On the other hand, for the hyperon sector, central two-body potentials that reproduce the experimental data on hypernuclei are employed as the Λ-nucleon, Σ − -nucleon and ΛΛ interactions. Since there are no experimental data on the odd-state component of the ΛΛ interaction, we prepare four odd-state ΛΛ interaction models, and calculate four EOSs of hyperonic nuclear matter for those interactions using the cluster variational method. The obtained maximum mass of NSs increases as the odd-state ΛΛ interaction becomes more repulsive, although it is still smaller than the recently observed masses of heavy NSs. Moreover, the critical density of Σ − strongly depends on the odd-state ΛΛ interaction. A phenomenological three-baryon repulsive force is employed in our variational calculations to explain the observed data on heavy NSs.

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Section: Numerical Results and Discussionsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Variational Approach to Neutron Star Matter with Hyperons

Togashi¹,

Hiyama²,

Yamamoto³

et al. 2017

Proceedings of the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015)

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show abstract

“…Since then the ΛNN interaction received considerable attention in many other studies of hypernuclei [35][36][37][38][39][40][41][42][43]. It is thus quite natural to expect that YTBIs can influence the EoS of dense matter and can represent a likely candidate to solve the hyperon puzzle [45][46][47][48]. This idea was advocated [49] even before the measurements of NSs with M ∼ 2 M sun [2,3].…”

Section: Hyperon Starsmentioning

confidence: 99%

The Hyperon Puzzle in Neutron Stars

Bombaci

2017

Proceedings of the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015)

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The so called hyperon puzzle, i.e. the difficulty to reconcile the measured masses of neutron stars (NSs) with the presence of hyperons in their interiors, is one of the hot topics in astrophysics which is stimulating copious experimental and theoretical research in hypernuclear physics. After illustrating the origin of the hyperon puzzle, I discuss some of its possible solutions, and particularly those related to the role of hyperonic two-and three-body interactions on the equation of state of dense matter. Afterward, I discuss a possibility to circumvent the hyperon puzzle allowing for the presence of strangeness in NSs in the form of deconfined strange quark matter, and thus considering the so called quark stars, i.e. hybrid stars or strange stars. Finally I discuss the astrophysical consequences of the possible conversion process of an hadronic star to a quark star.

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“…A aration energies of hypernuclei give very different results for the properties of the infinite medium [52]. We define the total baryon density ρ and the Λ fraction x as:…”

Section: Neutron Matter At High Densitymentioning

confidence: 99%

The EOS of Neutron Matter and the Effect of Λ Hyperons to Neutron Star Structure

Gandolfi

Lonardoni

2017

Proceedings of the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015)

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The structure of neutron stars is determined by the equation of state of the matter inside the star, which relies on the knowledge of nuclear interactions. While radii of neutron stars mostly depend on the equation of state of neutron matter at nuclear densities, their maximum mass can be drastically affected by the appearance of hyperons at higher densities in the inner core of the star. We summarize recent quantum Monte Carlo results on the calculation of the equation of state of neutron matter at nuclear and higher densities. We report about the development of realistic hyperon-nucleon interactions based on the available experimental data for light-and medium-heavy hypernuclei and on the effect of Λ hyperons to the neutron star structure.

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Hyperon Puzzle: Hints from Quantum Monte Carlo Calculations

Cited by 281 publications

References 64 publications

Variational Approach to Neutron Star Matter with Hyperons

Variational Approach to Neutron Star Matter with Hyperons

The Hyperon Puzzle in Neutron Stars

The EOS of Neutron Matter and the Effect of Λ Hyperons to Neutron Star Structure

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