Three-body forces acting on a \(\varLambda \) hyperon in a nuclear medium are investigated, with special focus on the so-called hyperon puzzle in neutron stars. The hyperon–nucleon two-body interaction deduced from SU(3) chiral effective field theory is employed at next-to-leading order. Hyperon–nucleon three-body forces are approximated using saturation by decuplet baryons and are transcribed to density-dependent effective two-body interactions. These together are taken as input in a Brueckner–Bethe–Goldstone equation with explicit treatment of the \(\varLambda N\leftrightarrow \varSigma N\) and \(\varLambda NN\leftrightarrow \varSigma NN\) coupled channels. Single-particle potentials of a \(\varLambda \) hyperon in symmetric nuclear matter and neutron matter are calculated. With parameters of the \(\varLambda NN\) three-body force constrained by hypernuclear phenomenology, extrapolations to high baryon density are performed. By comparison of the \(\varLambda \) and neutron chemical potentials at densities characteristic of the core of neutron stars it is found that the combined repulsive effects of two- and three-body correlations can make the appearance of \(\varLambda \) hyperons in neutron stars energetically unfavourable, thus potentially offering a possible answer to a longstanding query.

中文翻译：

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Hyperon-核子三体力与中子星的奇异

研究了作用在核介质中\（\ varLambda \）超子上的三体力，特别关注中子星中的所谓的超子难题。从SU（3）手性有效场理论推导的超子-核子两体相互作用以次要顺序使用。Hyperon-核子三体力使用十重子重子使用饱和度进行近似，并转换为依赖密度的有效两体相互作用。这些一起作为Brueckner–Bethe–Goldstone方程的输入，对\（\ varLambda N \ leftrightarrow \ varSigma N \）和\（\ varLambda NN \ leftrightarrow \ varSigma NN \）耦合通道进行了显式处理。\（\ varLambda \）的单粒子电势计算了对称核物质和中子物质中的超子。利用受超核现象学约束的\（\ varLambda NN \）三体力的参数，可以推断高重子密度。通过比较中子星核密度特征的\（\ varLambda \）和中子化学势，发现两体和三体相关性的组合排斥作用可以使\（\ varLambda \）出现中子星中的高子在能量上不利，因此可能为长期存在的问题提供可能的答案。