Hyperon puzzle of neutron stars with Skyrme force models

Yeunhwan Lim; Chang Ho Hyun; Kyujin Kwak; Chang Hwan Lee

doi:10.1142/S0218301315501001

Hyperon puzzle of neutron stars with Skyrme force models

Yeunhwan Lim, Chang Ho Hyun, Kyujin Kwak, Chang Hwan Lee

Department of Science Education

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28 Scopus citations

Abstract

We consider the so-called hyperon puzzle of neutron star (NS). We employ Skyrme force models for the description of in-medium nucleon-nucleon (NN), nucleon-Lambda hyperon (Nλ) and Lambda-Lambda (λλ) interactions. A phenomenological finite-range force (FRF) for the λλ interaction is considered as well. Equation of state (EoS) of NS matter is obtained in the framework of density functional theory, and Tolman-Oppenheimer-Volkoff (TOV) equations are solved to obtain the mass-radius relations of NSs. It has been generally known that the existence of hyperons in the NS matter is not well supported by the recent discovery of large-mass NSs (M ≃ 2M_⊙) since hyperons make the EoS softer than the one without them. For the selected interaction models, Nλ interactions reduce the maximum mass of NS by about 30%, while λλ interactions can give about 10% enhancement. Consequently, we find that some Skyrme force models predict the maximum mass of NS consistent with the observation of 2M_⊙ NSs, and at the same time satisfy observationally constrained mass-radius relations.

Original language	English
Article number	1550100
Journal	International Journal of Modern Physics E
Volume	24
Issue number	12
DOIs	https://doi.org/10.1142/S0218301315501001
State	Published - 1 Dec 2015

Bibliographical note

Funding Information:
∗Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Republic of Korea †Department of Physics Education, Daegu University, Gyeongsan 712-714, Republic of Korea ‡School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea

Funding Information:
YL was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science, ICT and Future Planning and National Research Foundation of Korea (NRF) (2013M7A1A1075764). CHH is grateful to the Institute for Basic Science, where part of the work was completed. Work of CHH was supported by Basic Science Research Program through the NRF funded by the Ministry of Education (NRF-2014R1A1A2054096). KK was supported by Basic Science Research Program through the NRF funded by the Ministry of Science, ICT and Future Planning (NRF-2014M1A7A1A03029872). CHL was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (Grant No. NRF-2015R1A2A2A01004238).

Publisher Copyright:
© 2015 World Scientific Publishing Company.

Keywords

Hyperons
neutron stars
nuclear matter

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10.1142/S0218301315501001

Cite this

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title = "Hyperon puzzle of neutron stars with Skyrme force models",

abstract = "We consider the so-called hyperon puzzle of neutron star (NS). We employ Skyrme force models for the description of in-medium nucleon-nucleon (NN), nucleon-Lambda hyperon (Nλ) and Lambda-Lambda (λλ) interactions. A phenomenological finite-range force (FRF) for the λλ interaction is considered as well. Equation of state (EoS) of NS matter is obtained in the framework of density functional theory, and Tolman-Oppenheimer-Volkoff (TOV) equations are solved to obtain the mass-radius relations of NSs. It has been generally known that the existence of hyperons in the NS matter is not well supported by the recent discovery of large-mass NSs (M ≃ 2M⊙) since hyperons make the EoS softer than the one without them. For the selected interaction models, Nλ interactions reduce the maximum mass of NS by about 30%, while λλ interactions can give about 10% enhancement. Consequently, we find that some Skyrme force models predict the maximum mass of NS consistent with the observation of 2M⊙ NSs, and at the same time satisfy observationally constrained mass-radius relations.",

keywords = "Hyperons, neutron stars, nuclear matter",

author = "Yeunhwan Lim and Hyun, {Chang Ho} and Kyujin Kwak and Lee, {Chang Hwan}",

note = "Funding Information: ∗Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Republic of Korea †Department of Physics Education, Daegu University, Gyeongsan 712-714, Republic of Korea ‡School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea Funding Information: YL was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science, ICT and Future Planning and National Research Foundation of Korea (NRF) (2013M7A1A1075764). CHH is grateful to the Institute for Basic Science, where part of the work was completed. Work of CHH was supported by Basic Science Research Program through the NRF funded by the Ministry of Education (NRF-2014R1A1A2054096). KK was supported by Basic Science Research Program through the NRF funded by the Ministry of Science, ICT and Future Planning (NRF-2014M1A7A1A03029872). CHL was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (Grant No. NRF-2015R1A2A2A01004238). Publisher Copyright: {\textcopyright} 2015 World Scientific Publishing Company.",

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doi = "10.1142/S0218301315501001",

language = "English",

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N2 - We consider the so-called hyperon puzzle of neutron star (NS). We employ Skyrme force models for the description of in-medium nucleon-nucleon (NN), nucleon-Lambda hyperon (Nλ) and Lambda-Lambda (λλ) interactions. A phenomenological finite-range force (FRF) for the λλ interaction is considered as well. Equation of state (EoS) of NS matter is obtained in the framework of density functional theory, and Tolman-Oppenheimer-Volkoff (TOV) equations are solved to obtain the mass-radius relations of NSs. It has been generally known that the existence of hyperons in the NS matter is not well supported by the recent discovery of large-mass NSs (M ≃ 2M⊙) since hyperons make the EoS softer than the one without them. For the selected interaction models, Nλ interactions reduce the maximum mass of NS by about 30%, while λλ interactions can give about 10% enhancement. Consequently, we find that some Skyrme force models predict the maximum mass of NS consistent with the observation of 2M⊙ NSs, and at the same time satisfy observationally constrained mass-radius relations.

AB - We consider the so-called hyperon puzzle of neutron star (NS). We employ Skyrme force models for the description of in-medium nucleon-nucleon (NN), nucleon-Lambda hyperon (Nλ) and Lambda-Lambda (λλ) interactions. A phenomenological finite-range force (FRF) for the λλ interaction is considered as well. Equation of state (EoS) of NS matter is obtained in the framework of density functional theory, and Tolman-Oppenheimer-Volkoff (TOV) equations are solved to obtain the mass-radius relations of NSs. It has been generally known that the existence of hyperons in the NS matter is not well supported by the recent discovery of large-mass NSs (M ≃ 2M⊙) since hyperons make the EoS softer than the one without them. For the selected interaction models, Nλ interactions reduce the maximum mass of NS by about 30%, while λλ interactions can give about 10% enhancement. Consequently, we find that some Skyrme force models predict the maximum mass of NS consistent with the observation of 2M⊙ NSs, and at the same time satisfy observationally constrained mass-radius relations.

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KW - nuclear matter

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JO - International Journal of Modern Physics E

JF - International Journal of Modern Physics E

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ER -

Hyperon puzzle of neutron stars with Skyrme force models

Abstract

Bibliographical note

Keywords

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