Hypernuclear matter in a complete SU(3) symmetry group

Lopes, Luiz L.; Menezes, D. P.

doi:10.1103/physrevc.89.025805

Cited by 108 publications

(131 citation statements)

References 86 publications

(155 reference statements)

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“…In this respect, the inclusion of other degrees of freedom, such as the lightest eight baryons, is energetically favored, but the onset of hyperons softens the equations of state and consequently reduces the maximum stellar masses [68]. Having in mind the description of two recently detected neutron stars with masses of the order of 2M [69,70], appropriate equations of state with the inclusion of hyperons were shown to strongly depend on the choice of the models and also on the hyperon-meson coupling constants [71][72][73]. After the comprehensive analyses performed in the present work, we suggest that the models that passed all tests be used in further studies involving the inclusion of hyperons in astrophysical applications.…”

Section: Discussionmentioning

confidence: 99%

Relativistic mean-field hadronic models under nuclear matter constraints

et al. 2014

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Background:The microscopic composition and properties of infinite hadronic matter at a wide range of densities and temperatures have been subjects of intense investigation for decades. The equation of state (EoS) relating pressure, energy density, and temperature at a given particle number density is essential for modeling compact astrophysical objects such as neutron stars, core-collapse supernovae, and related phenomena, including the creation of chemical elements in the universe. The EoS depends not only on the particles present in the matter, but, more importantly, also on the forces acting among them. Because a realistic and quantitative description of infinite hadronic matter and nuclei from first principles in not available at present, a large variety of phenomenological models has been developed in the past several decades, but the scarcity of experimental and observational data does not allow a unique determination of the adjustable parameters. Purpose: It is essential for further development of the field to determine the most realistic parameter sets and to use them consistently. Recently, a set of constraints on properties of nuclear matter was formed and the performance of 240 nonrelativistic Skyrme parametrizations was assessed [M. Dutra et al., Phys. Rev. C 85, 035201 (2012)] in describing nuclear matter up to about three times nuclear saturation density. In the present work we examine 263 relativistic-mean-field (RMF) models in a comparable approach. These models have been widely used because of several important aspects not always present in nonrelativistic models, such as intrinsic Lorentz covariance, automatic inclusion of spin, appropriate saturation mechanism for nuclear matter, causality, and, therefore, no problems related to superluminal speed of sound in medium. Method: Three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives were used. The first set (SET1) was the same as used in assessing the Skyrme parametrizations. The second and third sets (SET2a and SET2b) were more suitable for analysis of RMF and included, up-to-date theoretical, experimental and empirical information. Results: The sets of updated constraints (SET2a and SET2b) differed somewhat in the level of restriction but still yielded only 4 and 3 approved RMF models, respectively. A similarly small number of approved Skyrme parametrizations were found in the previous study with Skyrme models. An interesting feature of our analysis 0556-2813/2014/90(5)/055203 (35) 055203-1 ©2014 American Physical Society M. DUTRA et al.PHYSICAL REVIEW C 90, 055203 (2014) has been that the results change dramatically if the constraint on the volume part of the isospin incompressibility (K τ,v ) is eliminated. In this case, we have 35 approved models in SET2a and 30 in SET2b. Conclusions: Our work provides a new insight into application of RMF models to properties of nuclear matter and brings into focus their problematic proliferation. The assessment performed in this wo...

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Section: Discussionmentioning

confidence: 99%

Relativistic mean-field hadronic models under nuclear matter constraints

et al. 2014

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“…Since we are dealing here with an effective model for interacting particles in matter, without any input about symmetry breaking effects in dense matter, there is no reason to assume any flavor SU(3)-symmetry for the effective interaction. In addition, the approach is inconsistent in the sense that symmetry constraints are imposed only for the isoscalar vector couplings with other prescriptions for the other channels, see also the discussion in [14] on this point. By the way, in the vector-isovector channel, a strict application of this procedure would lead to severe problems with the observed nuclear symmetry energy [10].…”

Section: Setup For the Hyperonic Interactionmentioning

confidence: 99%

“…In the literature, SU(6)-symmetry is mostly imposed to fix the couplings, i.e. z 1 6 = , and only recent studies in view of the observation of high mass neutron stars have relaxed this assumption, for example [10,14,32].…”

Section: Setup For the Hyperonic Interactionmentioning

confidence: 99%

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Hyperons in neutron star matter within relativistic mean-field models

et al. 2015

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The attribute of rotational profile to the hyperon puzzle in the prediction of heaviest compact star M. Bhuyan et al Since the discovery of neutron stars with masses around M 2 ⊙ the composition of matter in the central part of these massive stars has been intensively discussed. Within this paper we will (re)investigate the question of the appearance of hyperons. To that end we will perform an extensive parameter study within relativistic mean field models. We will show that it is possible to obtain high mass neutron stars with (i) a substantial amount of hyperons, (ii) radii of 12-13 km for the canonical mass of M 1.4 ⊙ , and (iii) a spinodal instability at the onset of hyperons. The results depend strongly on the interaction in the hyperon-hyperon channels, on which only very little information is available from terrestrial experiments up to now.

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“…Among them of great contemporary interest is the nuclear symmetry energy E S [8], which has been investigated extensively within both phenomenological approaches and microscopic many-body theories using almost all available effective and/or realistic nuclear interactions, see, e.g., Refs. [9][10][11][12][13][14]. Due …”

Section: Introductionmentioning

confidence: 99%

Impact of Fock terms on the isospin properties of nuclear matter

Sun

Zhao

Long

2016

EPJ Web of Conferences

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Several topics on the isospin properties of nuclear matter studied within the density-dependent relativistic Hartree-Fock theory are summarized. In detail, the effects of the Fock terms on the nuclear symmetry energy are listed, including the extra enhancement from the Fock terms of the isoscalar meson-nucleon coupling channels, the extra hyperon-induced suppression effect originating from the Fock channel, self-consistent tensor effects embedded automatically in the Fock diagrams, the enhanced density-dependent isospin-triplet potential part of the symmetry energy at high densities, a reduced kinetic symmetry energy at supranuclear density and so on. The results demonstrate the importance of the Fork diagram, especially from the isoscalar mesonnucleon coupling channels, on the isospin properties of the in-medium nuclear force.The isospin properties of nuclear matter, such as the nuclear symmetry energy, the nucleon isovector (symmetry) potential, and the neutron-proton effective mass splitting, play essential roles in studying several topics of nuclear structure, nuclear reactions and nuclear astrophysics [1][2][3][4][5][6][7]. Among them of great contemporary interest is the nuclear symmetry energy E S [8], which has been investigated extensively within both phenomenological approaches and microscopic many-body theories using almost all available effective and/or realistic nuclear interactions, see, e.g., Refs. [9][10][11][12][13][14]. Due F -to our limited knowledge about the in-medium effects of nucleon-nucleon (NN) interactions and correlations along with technical difficulties to treat quantum many-body systems accurately, distinct deviations of predicted E S values appear beyond the nuclear saturation density ρ 0 .For the description of the structural properties of nuclear systems, the covariant density functional (CDF) theory has achieved great success during recent decades [15][16][17][18][19][20][21][22][23]. One of the most popular representatives is the relativistic Hartree approach with the no-sea approximation, namely, the relativistic mean field (RMF) theory [15,[24][25][26]. However, due to the limit of the approach itself, significant system degrees of freedom are missing in RMF, such as the one-pion exchange. The non-local effects of nuclear forces and the momentum dependence of self-energies are also hardly to be treated. With the growth of computational facilities and the development of new methods, such defects can be eliminated with the inclusion of exchange (Fock) terms, which generates a new CDF model -the relativistic Hartree-Fock (RHF) theory with density-dependent meson-nucleon couplings (i.e., the DDRHF theory) [27]. Substantial improvements are gained by DDRHF in the selfconsistent description of the ground state properties [27][28][29][30][31][32][33][34][35][36][37][38], the excitation modes [39][40][41][42] of finite nuclei and nuclear astrophysics as well [43][44][45][46].It has been shown from several studies that the inclusion of the Fock terms in the CDF theory could ...

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Hypernuclear matter in a complete SU(3) symmetry group

Cited by 108 publications

References 86 publications

Relativistic mean-field hadronic models under nuclear matter constraints

Relativistic mean-field hadronic models under nuclear matter constraints

Hyperons in neutron star matter within relativistic mean-field models

Impact of Fock terms on the isospin properties of nuclear matter

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