EFFECTS OF HYPERON MIXING ON NEUTRON STAR PROPERTIES

2008 ◽  
Vol 17 (09) ◽  
pp. 1739-1752
Author(s):  
TATSUYUKI TAKATSUKA
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Quark Model ◽  
Body Force ◽  
String Junction ◽  
Promising Candidate ◽  
Fermi Surfaces ◽  
Realistic Approach ◽  
Three Body

From a serious inconsistency between theory and observations for the mass of hyperon-mixed neutron stars (NSs), it is stressed that some "extra repulsion" is missing in hypernuclear systems and three-body force repulsion is tested for the cases with phenomenological Illinoi's type, 2π-exchange via Δ-excitation type(2πΔ) and string-junction quark model(SJM). It is remarked that the "extra repulsion" should have a nature to act universally, i.e., independent of baryon species. The SJM three-body repulsion can meet the condition because of flavor-independence and {2πΔ+ SJM } scheme is shown to be a promising candidate for the "extra repulsion". Occurence of Λ and Σ- superfluidities are shown also by a realistic approach, which importantly supports the idea of nonstandard fast "hyperon cooling" scenario to explain colder class NSs. However, less attractive ΛΛ interaction suggested by the "NAGARA event" [Formula: see text] leads to the disappearance of Λ superfluidity and the breaking down of the scenario. In this connection, the revival of "Λ superfluidity" due to ΛΣ- pairing instead of ΛΛ one is discussed in a new scheme of "bubble shell" hypothesis where the matching of two different Fermi surfaces is forced.

ΛΣ− PAIRING IN “BUBBLE FERMI SHELL” SCHEME

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2473-2476 ◽  
Author(s):  
TATSUYUKI TAKATSUKA ◽  
RYOZO TAMAGAKI
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Superfluid State ◽  
Fermi Surfaces ◽  
Realistic Approach

In neutron star cores, superfluid state of hyperons such as lambda (Λ) and sigma-minus (Σ−) has been shown to realize by a realistic approach. This result importantly supports the idea of nonstandard fast “hyperon cooling” scenario to explain colder class neutron stars observed. However, a less attractive ΛΛ interaction suggested by a double Λ hypernucleus ([Formula: see text]; “NAGARA” event) leads to a disappearance of Λ superfluidity and thereby the breaking down of the scenario. In this connection, the revival of “Λ superfluidity” due to the ΛΣ− pairing, instead of ΛΛ one, is discussed in a new scheme of “bubble Fermi shell” hypothesis where the matching of two different Fermi surfaces is forced.

scholarly journals Constraints on Microscopic and Phenomenological Equations of State of Dense Matter from GW170817

Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 204 ◽  
Author(s):  
Domenico Logoteta ◽  
Ignazio Bombaci
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Equations Of State ◽  
Mean Field ◽  
Dense Matter ◽  
Neutron Star Matter ◽  
Field Approach ◽  
Relativistic Mean Field ◽  
Three Body ◽  
Good Agreement

We discuss the constraints on the equation of state (EOS) of neutron star matter obtained by the data analysis of the neutron star-neutron star merger in the event GW170807. To this scope, we consider two recent microscopic EOS models computed starting from two-body and three-body nuclear interactions derived using chiral perturbation theory. For comparison, we also use three representative phenomenological EOS models derived within the relativistic mean field approach. For each model, we determine the β -stable EOS and then the corresponding neutron star structure by solving the equations of hydrostatic equilibrium in general relativity. In addition, we calculate the tidal deformability parameters for the two neutron stars and discuss the results of our calculations in connection with the constraints obtained from the gravitational wave signal in GW170817. We find that the tidal deformabilities and radii for the binary’s component neutron stars in GW170817, calculated using a recent microscopic EOS model proposed by the present authors, are in very good agreement with those derived by gravitational waves data.

The baryonic spectrum in a constituent quark model including a three-body force

1992 ◽  
Vol 343 (3) ◽  
pp. 331-336 ◽  
Author(s):  
B. Desplanques ◽  
C. Gignoux ◽  
B. Silvestre-Brac ◽  
P. Gonz�lez ◽  
J. Navarro ◽  
...  
Keyword(s):  
Quark Model ◽  
Body Force ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Three Body

scholarly journals Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

2018 ◽  
Vol 609 ◽  
pp. A128 ◽  
Author(s):  
Ignazio Bombaci ◽  
Domenico Logoteta
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Symmetric Nuclear Matter ◽  
Heavy Nuclei ◽  
Hartree Fock ◽  
Binary Neutron Star ◽  
Dense Nuclear Matter ◽  
Three Body

Aims. We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods. The EOS is derived using the Brueckner–Bethe–Goldstone quantum many-body theory in the Brueckner–Hartree–Fock approximation. Neutron star properties are next computed solving numerically the Tolman–Oppenheimer–Volkov structure equations. Results. Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to ~4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

CONSISTENT THREE-BODY FORCE WITH BONN B POTENTIAL AND NEUTRON STAR STRUCTURE

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1727-1733 ◽  
Author(s):  
Z. H. LI ◽  
U. LOMBARDO ◽  
H.-J. SCHULZE ◽  
W. ZUO
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Symmetry Energy ◽  
Body Force ◽  
Nucleon Force ◽  
Nucleon Potential ◽  
Saturation Properties ◽  
Nuclear Equation Of State ◽  
Neutron Star Mass ◽  
Three Body

Microscopic three-nucleon force consistent with the Bonn B two-nucleon potential is constructed, which includes Δ(1232), Roper, and nucleon-antinucleon excitation contributions. Recent results for the choice of the meson parameters are discussed. The forces are used in Brueckner calculations and the saturation properties of nuclear matter are determined. At the high densities, the nuclear equation of state and the symmetry energy are calculated. The corresponding neutron star mass-radius relations are presented.

scholarly journals Impact of chiral hyperonic three-body forces on neutron stars

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
Domenico Logoteta ◽  
Isaac Vidaña ◽  
Ignazio Bombaci
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nucleon Nucleon ◽  
Effective Field ◽  
Many Body ◽  
Chiral Effective Field Theory ◽  
Hartree Fock ◽  
The Many ◽  
Three Body

Abstract.We study the effects of the nucleon-nucleon-lambda (NN$ \Lambda$Λ three-body force on neutron stars. In particular, we consider the NN$ \Lambda$Λ force recently derived by the Jülich-Bonn-Munich group within the framework of chiral effective field theory at next-to-next-to-leading order. This force, together with realistic nucleon-nucleon, nucleon-nucleon-nucleon and nucleon-hyperon interactions, is used to calculate the equation of state and the structure of neutron stars within the many-body non-relativistic Brueckner-Hartree-Fock approach. Our results show that the inclusion of the NN$ \Lambda$Λ force leads to an equation of state stiff enough such that the resulting neutron star maximum mass is compatible with the largest currently measured ( $ \sim 2 M_\odot$∼2M⊙ neutron star masses. Using a perturbative many-body approach we calculate also the separation energy of the $ \Lambda$Λ in some hypernuclei finding that the agreement with the experimental data improves for the heavier ones when the effect of the NN$ \Lambda$Λ force is taken into account.

3 PF 2 neutron superfluidity in neutron stars and three-body force effect

2008 ◽  
Vol 17 (9) ◽  
pp. 3289-3293 ◽  
Author(s):  
Cui Chang-Xi ◽  
Zuo Wei ◽  
H. J Schulze
Keyword(s):  
Neutron Stars ◽  
Body Force ◽  
Force Effect ◽  
Three Body
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