Eur. Phys. J. A (2016) 52: 19
https://doi.org/10.1140/epja/i2016-16019-0

Regular Article - Theoretical Physics

Hyperon-mixed neutron star with universal many-body repulsion

¹ Nishina Center for Accelerator-Based Science, Institute for Physical and Chemical Research (RIKEN), 351-0198, Wako, Saitama, Japan
² National Institute of Technology, Ichinoseki College, 021-8511, Ichinoseki, Iwate, Japan
³ Department of Physics, Chiba Institute of Technology, 2-1-1 Shibazono Narashino, 275-0023, Chiba, Japan
⁴ IMAPP, University of Nijmegen, Nijmegen, The Netherlands

^* e-mail: ys_yamamoto@riken.jp

Received: 28 July 2015
Accepted: 14 October 2015
Published online: 3 February 2016

Abstract

Neutron stars with large masses require the hard stiffness of equation of state (EoS) of neutron-star matter. On the other hand, hyperon mixing brings about remarkable softening of EoS. In order to solve this problem, a multi-pomeron exchange potential (MPP) is introduced as a model for the universal many-body repulsion in baryonic systems on the basis of the Extended Soft Core (ESC) baryon-baryon interaction. The strength of MPP is determined by analyzing the nucleus-nucleus scattering with the G -matrix folding model. The interactions in , and channels are shown to be consistent with experimental indications. The EoS in neutron-star matter with hyperon mixing is obtained from ESC in addition of MPP, and mass-radius relations of neutron stars are derived. The maximum mass is shown to reach even in the case of including hyperon mixing on the basis of model-parameters determined by terrestrial experiments.