Effective interactions of hyperons and mass-radius relation of neutron stars

Yeunhwan Lim, Chang-Hwan Lee, and Yongseok Oh
Phys. Rev. D 97, 023010 – Published 18 January 2018

Abstract

We examine the role of hyperons in a neutron star based on the relativistic mean field approach. For nuclear matter below 1.5 times the normal nuclear density we constrain the model parameters by using the symmetric nuclear matter properties and theoretical investigations for neutron matter in the literature. We then extend the model to higher densities by including hyperons and isoscalar vector mesons that contain strangeness degree of freedom. We confirm that the ϕ meson induces a Λ repulsive force and hardens the equation of state. The hardening arising from the ϕ meson compensates the softening from the existence of hyperons. The flavor SU(3) and spin-flavor SU(6) relations are examined as well. We found that the coupling constants fitted by neutron matter properties could yield high enough maximum mass of a neutron star and the obtained results satisfy both the mass and radius constraints. The onset of the hyperon direct Urca process in neutron stars is also investigated using our parametrization.

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  • Received 9 August 2017

DOI:https://doi.org/10.1103/PhysRevD.97.023010

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Nuclear PhysicsParticles & FieldsGravitation, Cosmology & Astrophysics

Authors & Affiliations

Yeunhwan Lim1,*, Chang-Hwan Lee2,†, and Yongseok Oh3,4,‡

  • 1Cyclotron Institute and Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
  • 2Department of Physics, Pusan National University, Busan 46241, Korea
  • 3Department of Physics, Kyungpook National University, Daegu 41566, Korea
  • 4Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk 37673, Korea

  • *ylim@tamu.edu
  • clee@pusan.ac.kr
  • yohphy@knu.ac.kr

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Issue

Vol. 97, Iss. 2 — 15 January 2018

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