Lambda-nuclear interactions and hyperon puzzle in neutron stars

• Published in: The European physical journal. A, Hadrons and nuclei Hadrons and nuclei, 2017-06, Vol.53 (6), p.1-6, Article 121
• Main Authors: Haidenbauer, J., Meißner, U. -G., Kaiser, N., Weise, W.
• Format: Article
• Language: English
• Subjects: Density; Field theory; Hadrons; Heavy Ions; Neutron stars; Neutrons; Nuclear Fusion; Nuclear interactions; Nuclear matter; Nuclear Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Quarks; Regular Article - Theoretical Physics
• ISSN: 1434-6001; 1434-601X
• DOI: 10.1140/epja/i2017-12316-4

. Brueckner theory is used to investigate the in-medium properties of a Λ -hyperon in nuclear and neutron matter, based on hyperon-nucleon interactions derived within SU (3) chiral effective field theory (EFT). It is shown that the resulting Λ single-particle potential U Λ ( p Λ = 0 , ρ ) becomes strongly repulsive for densities ρ of two-to-three times that of normal nuclear matter. Adding a density-dependent effective Λ N -interaction constructed from chiral Λ N N three-body forces increases the repulsion further. Consequences of these findings for neutron stars are discussed. It is argued that for hyperon-nuclear interactions with properties such as those deduced from the SU (3) EFT potentials, the onset for hyperon formation in the core of neutron stars could be shifted to much higher density which, in turn, could pave the way for resolving the so-called hyperon puzzle.