Speaker
Description
To study the structure of neutron stars, it is important to consider the hyperons that are expected to appear in the core to suppress the high Fermi energy of neutrons. In particular, since the observation of a neutron star having twice solar mass in 2010, there has been much discussion about how to compensate for the drop in the pressure of the star caused by the appearance of hyperons, and the importance of the three-body force including hyperons has been actively discussed. In this situation, deriving reliable two-body hyperon-nucleon interactions is indispensable for discussing the structure of neutron stars and the three-body force. So far, the hyperon-nucleon interaction has been extracted from the structure of hypernuclei, but it has not yet been accurately determined due to the uncertainty of deriving two-body forces from many-body systems. We aim to establish the hyperon-nucleon interaction from two-body scattering data of hyperons and nucleons, and are promoting hyperon-proton scattering experiments. In the Σ- proton scattering experiment at J-PARC, we have succeeded in measuring the differential cross sections for Σ-p, Σ+p elastic scatterings and Σ-p→Λn inelastic scattering with unprecedented precision in the Σ momentum range of 0.45-0.8 GeV/c. Using our data, the chiral hyperon-nucleon interaction has been extended to NNLO. In order to elucidate the ΛN interaction, which is the most important of the hyperon-nucleon interactions, through scattering experiments, we have currently launched a Λ-proton scattering experiment using photo-produced Λ at SPring-8. In parallel with these scattering experiments, we are also conducting collaborative research to derive the YN interaction from lattice QCD and the ΣN cusp measurement as the comprehensively study of interactions of strangeness −1 sector.
In this talk, I will introduce our research for establishing hyperon-nucleon interactions, focusing on the results so far and the current progress of hyperon-nucleon scattering experiments, and also discuss its relevance to neutron star research.
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