Light clusters in dilute heavy-baryon admixed nuclear matter

Sedrakian, Armen

doi:10.1140/epja/s10050-020-00262-1

Cited by 19 publications

(10 citation statements)

References 73 publications

(64 reference statements)

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“…It is further seen that finite temperatures induce a significant shift of the hyperon thresholds to lower densities (which lie outside of the density range considered). This is in accordance with the recent observation that low-density hot nuclear matter may feature a significant fraction of strangeness (Λ-particles) as well as ∆-resonances in addition to light clusters and free nucleons [70]. Note also that the Λ-hyperon abundances become larger than those of neutrons at high density, i.e., these species are the dominant baryonic component in the matter for n B /n sat 5.5.…”

Section: Numerical Resultssupporting

confidence: 91%

Equation of State and Composition of Proto-Neutron Stars and Merger Remnants with Hyperons

Sedrakian

Harutyunyan

2021

Universe

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Finite-temperature equation of state (EoS) and the composition of dense nuclear and hypernuclear matter under conditions characteristic of neutron star binary merger remnants and supernovas are discussed. We consider both neutrino free-streaming and trapped regimes which are separated by a temperature of a few MeV. The formalism is based on covariant density functional (CDF) theory for the full baryon octet with density-dependent couplings, suitably adjusted in the hypernuclear sector. The softening of the EoS with the introduction of the hyperons is quantified under various conditions of lepton fractions and temperatures. We find that Λ, Ξ−, and Ξ0 hyperons appear in the given order with a sharp density increase at zero temperature at the threshold being replaced by an extended increment over a wide density range at high temperatures. The Λ hyperon survives in the deep subnuclear regime. The triplet of Σs is suppressed in cold hypernuclear matter up to around seven times the nuclear saturation density, but appears in significant fractions at higher temperatures, T≥20 MeV, in both supernova and merger remnant matter. We point out that a special isospin degeneracy point exists where the baryon abundances within each of the three isospin multiplets are equal to each other as a result of (approximate) isospin symmetry. At that point, the charge chemical potential of the system vanishes. We find that under the merger remnant conditions, the fractions of electron and μ-on neutrinos are close and are about 1%, whereas in the supernova case, we only find a significant fraction (∼10%) of electron neutrinos, given that in this case, the μ-on lepton number is zero.

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Section: Numerical Resultssupporting

confidence: 91%

Equation of State and Composition of Proto-Neutron Stars and Merger Remnants with Hyperons

Sedrakian

Harutyunyan

2021

Universe

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“…It is further seen that finite temperatures induce a significant shift of the hyperon thresholds to lower densities (which lie outside of the density range considered). This is in accord with the recent observation that the low-density hot nuclear matter may feature a significant fraction of strangeness (Λ-particles) as well as ∆-resonances in addition to cluster and free nucleons [70]. Note also that the Λ-hyperon abundances become larger than those of neutrons at high density, i.e., these species are the dominant baryonic component in the matter for n B /n sat 5.5.…”

Section: Numerical Resultssupporting

confidence: 90%

Equation of state and composition of proto-neutron stars and merger remnants with hyperons

Sedrakian,

Harutyunyan

2021

Preprint

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Finite-temperature equation of state (EoS) and composition of dense nuclear and hypernuclear matter under conditions characteristic for neutron star binary merger remnants and supernovas are discussed. We consider both the neutrino free-streaming and the trapped regimes which are separated by a temperature of a few MeV. The formalism is based on covariant density functional (CDF) theory for the full baryon octet with density-dependent couplings, suitably adjusted in the hypernuclear sector. The softening of the EoS with the introduction of the hyperons is quantified under various conditions of lepton fractions and temperatures. We find that Λ, Ξ − , and Ξ 0 hyperons appear in the given order with the sharp density increase at zero temperature at the threshold being replaced by an extended increment over a wide density range at high temperatures. The Λ hyperon survives in the deep subnuclear regime. The triplet of Σs is suppressed in cold hypernuclear matter up to around seven times the nuclear saturation density, but appears in significant fractions at higher temperatures T ≥ 20 MeV in both supernova and merger remnant matter. We point out that there exists a special isospin degeneracy point where the baryon abundances within each of the three isospin-multiplets are equal to each other as a result of (approximate) isospin symmetry. At that point the charge chemical potential of the system vanishes. We find that under the merger remnant conditions the fractions of electron and µ-on neutrinos are close and are about 1%, whereas in the supernova case, we find only a significant fraction (∼10%) of electron neutrinos, given that in this case, the µ-on lepton number is zero.

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“…3 that hyperon and ∆resonance thresholds are absent and they propagate up to the lower bound of the density range considered. A hint on the presence of these species at lower densities is provided by the recent observation that the low-density hot nuclear matter contains a significant fraction of strangeness (Λparticles) as well as ∆-resonances in addition to clusters and free nucleons [65].…”

Section: Numerical Resultsmentioning

confidence: 99%

Delta-resonances and hyperons in proto-neutron stars and merger remnants

Sedrakian¹,

Harutyunyan²

2022

Preprint

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The equation of state (EoS) and composition of dense and hot ∆-resonance admixed hypernuclear matter is studied under conditions that are characteristic of neutron star binary merger remnants and supernovas. The cold, neutrino free regime is also considered as a reference for the astrophysical constraints on the EoS of dense matter. Our formalism uses the covariant density functional (CDF) theory successfully adapted to include the full J P = 1/2 + baryon octet and non-strange members of J P = 3/2 + decouplet with density-dependent couplings that have been suitably adjusted to the existing laboratory and astrophysical data in the nuclear and hypernuclear sectors. The effect of ∆-resonances at finite temperatures is to soften the EoS of hypernuclear matter at intermediate densities and stiffen it at high densities. At low temperatures, the heavy baryons Λ, ∆ − ,Ξ − , Ξ 0 and ∆ 0 appear in the given order if the ∆-meson couplings are close to those for the nucleon-meson couplings. As is the case for hyperons, the thresholds of ∆-resonances move to lower densities with the increase of temperature indicating a significant fraction of ∆s in the low-density subnuclear regime. We find that the ∆-resonances comprise a significant fraction of baryonic matter, of the order of 10% at temperatures of the order of several tens of MeV in the neutrino-trapped regime and, thus, may affect the supernova and binary neutron star dynamics.PACS. 9 7.60.Jd (Neutron stars) -2 6.60.+c (Nuclear matter aspects of neutron stars) -2 1.65.+f (Nuclear matter)

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Light clusters in dilute heavy-baryon admixed nuclear matter

Cited by 19 publications

References 73 publications

Equation of State and Composition of Proto-Neutron Stars and Merger Remnants with Hyperons

Equation of State and Composition of Proto-Neutron Stars and Merger Remnants with Hyperons

Equation of state and composition of proto-neutron stars and merger remnants with hyperons

Delta-resonances and hyperons in proto-neutron stars and merger remnants

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